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Retail | Thornburg Global Opportunities Fund
Global Opportunities Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types from issuers around the world.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Global Opportunities Fund
Thornburg Global Opportunities Fund - Class A
Thornburg Global Opportunities Fund - Class C
Thornburg Global Opportunities Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Global Opportunities Fund
Thornburg Global Opportunities Fund - Class A
Thornburg Global Opportunities Fund - Class C
Thornburg Global Opportunities Fund - Class I
Management Fees 0.85% 0.85% 0.85%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses 0.21% 0.23% 0.21%
Total Annual Fund Operating Expenses 1.31% 2.08% 1.06%
Fee Waiver/Expense Reimbursement (0.07%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.31% 2.08% 0.99%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.99%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Global Opportunities Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Global Opportunities Fund - Class A 577 847 1,136 1,958
Thornburg Global Opportunities Fund - Class C 311 652 1,119 2,410
Thornburg Global Opportunities Fund - Class I 101 330 578 1,288

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Global Opportunities Fund | Thornburg Global Opportunities Fund - Class C | USD ($) 211 652 1,119 2,410
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 25.48% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goal by investing primarily in a broad range of equity securities, including common stocks, preferred stocks and publicly traded real estate investment trusts. The Fund may invest in any stock or other equity security which its investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), believes may assist the Fund in pursuing its goal, including smaller companies with market capitalizations less than $500 million.

The Fund portfolio includes investments in both domestic securities and securities of issuers domiciled in or economically tied to countries outside the United States, including developing countries. Relative proportions of each will vary from time to time, depending upon the advisor’s view of specific investment opportunities and macro-economic factors. Under normal market conditions, the Fund invests a significant portion of its assets in issuers domiciled in or economically tied to countries outside the United States.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for securities, and analysis of specific issuers.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Real Estate Risk – The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Global Opportunities Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the MSCI ACWI Net Total Return USD Index, which represents a broad measure of both domestic and foreign equity market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

21.72%

6/30/2020

Lowest Quarterly Results

(24.82)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Global Opportunities Fund
1 Year
5 Years
10 Years
Thornburg Global Opportunities Fund - Class A 9.25% 10.54% 12.31%
Thornburg Global Opportunities Fund - Class A | After Taxes on Distributions 5.72% 9.07% 11.47%
Thornburg Global Opportunities Fund - Class A | After Taxes on Distributions and Sales 7.53% 8.01% 10.05%
Thornburg Global Opportunities Fund - Class A | MSCI ACWI Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%
Thornburg Global Opportunities Fund - Class C 12.56% 10.73% 11.98%
Thornburg Global Opportunities Fund - Class C | MSCI ACWI Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%
Thornburg Global Opportunities Fund - Class I 14.75% 11.90% 13.23%
Thornburg Global Opportunities Fund - Class I | MSCI ACWI Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg International Equity Fund
International Equity Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.

The secondary, non-fundamental goal of the Fund is to seek some current income.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg International Equity Fund
Thornburg International Equity Fund - Class A
Thornburg International Equity Fund - Class C
Thornburg International Equity Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg International Equity Fund
Thornburg International Equity Fund - Class A
Thornburg International Equity Fund - Class C
Thornburg International Equity Fund - Class I
Management Fees 0.74% 0.74% 0.74%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses [1] 0.26% 0.22% 0.20%
Total Annual Fund Operating Expenses 1.25% 1.96% 0.94%
Fee Waiver/Expense Reimbursement (0.04%) [2]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.25% 1.96% 0.90%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes A, I and C would have been 0.59%, 0.52% and 0.50%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.90%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - Retail - Thornburg International Equity Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg International Equity Fund - Class A 572 829 1,105 1,893
Thornburg International Equity Fund - Class C 299 615 1,057 2,285
Thornburg International Equity Fund - Class I 92 296 516 1,151

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg International Equity Fund | Thornburg International Equity Fund - Class C | USD ($) 199 615 1,057 2,285
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 42.85% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests primarily in common stocks of non-U.S. companies and in depositary receipts associated with such stocks. The Fund may invest in developing countries, but under normal conditions those investments are expected to comprise a smaller proportion of the Fund than investments in developed countries. Under normal conditions, the Fund will invest at least 80% of its net assets in common stocks or depositary receipts.

The Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), intends to invest on an opportunistic basis where the Fund’s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks the Fund categorizes as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies.

Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund’s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

profitability

price/earnings ratio

price/book value ratio

price/cash flow ratio

debt/capital ratio

dividend characteristics

security and consistency of revenues

EV (enterprise value)/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio

undervalued assets

earnings growth potential

industry growth characteristics

industry leadership

franchise value

potential for favorable developments

EBIT (earnings before interest and taxes)/interest expense ratio

The Fund categorizes its equity investments in the following three categories:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth, profitability, cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its net assets in common stocks or depositary receipts may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Risks Affecting Investments in China – A significant portion of the Fund’s assets may be invested in companies exposed to China. Risks affecting investments in China include a potential downturn in the Chinese economy, reduced liquidity or increased price volatility in the Chinese securities markets as a result of trading suspensions affecting Chinese issuers or other factors, the potential that the Chinese government may expand restrictions on foreign investments or the repatriation of capital, and the implementation of new tariffs or other trade barriers by China or its trading partners. A lack of transparency respecting Chinese companies may also reduce the Fund’s ability to conduct diligence respecting those companies’ accounting and governance standards, which may in turn reduce the Fund’s ability to detect fraudulent practices that may adversely affect the companies’ stock prices.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the MSCI ACWI ex USA Net Total Return USD Index (primary index) and the MSCI EAFE Net Total Return USD Index (secondary index), each of which is a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Effective as of February 1, 2022, the MSCI ACWI ex USA Net Total Return USD Index replaced the MSCI EAFE Net Total Return USD Index as the Fund’s primary index. Thornburg believes that the MSCI ACWI ex USA Net Total Return USD Index more closely aligns with the Fund’s investment strategies than the MSCI EAFE Net Total Return USD Index.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

18.46%

6/30/2020

Lowest Quarterly Results

(20.94)%

9/30/2011

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg International Equity Fund
1 Year
5 Years
10 Years
Thornburg International Equity Fund - Class A 2.44% 10.01% 7.62%
Thornburg International Equity Fund - Class A | After Taxes on Distributions (1.50%) 7.52% 5.57%
Thornburg International Equity Fund - Class A | After Taxes on Distributions and Sales 2.73% 7.19% 5.49%
Thornburg International Equity Fund - Class A | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%
Thornburg International Equity Fund - Class A | MSCI EAFE Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%
Thornburg International Equity Fund - Class C 5.58% 10.23% 7.34%
Thornburg International Equity Fund - Class C | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%
Thornburg International Equity Fund - Class C | MSCI EAFE Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%
Thornburg International Equity Fund - Class I 7.60% 11.40% 8.51%
Thornburg International Equity Fund - Class I | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%
Thornburg International Equity Fund - Class I | MSCI EAFE Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Better World International Fund
Better World International Fund
Investment Goal

The Fund seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Better World International Fund
Thornburg Better World International Fund - Class A
Thornburg Better World International Fund - Class C
Thornburg Better World International Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Better World International Fund
Thornburg Better World International Fund - Class A
Thornburg Better World International Fund - Class C
Thornburg Better World International Fund - Class I
Management Fees 0.98% 0.98% 0.98%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses 0.34% 0.87% 0.23%
Total Annual Fund Operating Expenses 1.57% 2.85% 1.21%
Fee Waiver/Expense Reimbursement [1] (0.66%) (0.31%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.57% 2.19% 0.90%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class C and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 2.19% and 0.90%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year) your costs would be:

Expense Example - Retail - Thornburg Better World International Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Better World International Fund - Class A 603 923 1,267 2,233
Thornburg Better World International Fund - Class C 322 821 1,445 3,129
Thornburg Better World International Fund - Class I 92 353 635 1,438

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Better World International Fund | Thornburg Better World International Fund - Class C | USD ($) 222 821 1,445 3,129
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 119.96% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goal by investing primarily in a broad range of foreign equity securities or depositary receipts of foreign equity securities. When considering investments for the Fund, the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), combines fundamental research on issuers with analysis of significant environmental, social and governance (“ESG”) characteristics, which Thornburg defines as those ESG factors that may materially affect an issuer’s risk and return profile and, accordingly, the issuer’s long-term investment performance.

The Fund may invest in any stock or other equity security which Thornburg believes may assist the Fund in pursuing its goal, including common stocks, preferred stocks and publicly traded real estate investment trusts. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies. The Fund may also invest in developing country companies.

Thornburg intends to invest on an opportunistic basis where the Fund’s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks the Fund categorizes as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time.

The Fund categorizes its equity investments in the following three categories:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth, profitability, cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of Thornburg concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions also include consideration of domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for securities.

The Fund seeks to invest in companies which in Thornburg’s view are trading at discount to their intrinsic value and also demonstrate one or more significant positive ESG characteristics. Through Thornburg’s fundamental research process, Thornburg evaluates each potential investment based on a variety of factors, including traditional investment criteria such as the company’s ability to effectively allocate capital, willingness to pay dividends and repurchase shares, ability to sustain a competitive advantage, and ability to grow its core business. As part of its research process for the Fund’s investments, Thornburg also assesses each issuer’s ESG characteristics, focusing on those ESG characteristics which Thornburg believes are significant insofar as they are expected to materially affect the issuer’s investment performance. The specific ESG characteristics which Thornburg determines to be significant will vary over time and among different financial sectors and industries, but will generally include the following:

Environmental characteristics, such as an issuer’s emissions and energy management practices;

Social capital characteristics, such as an issuer’s data security and privacy practices;

Human capital characteristics, such as an issuer’s labor practices;

Business model and innovation characteristics, such as an issuer’s supply chain management practices; and

Leadership and governance characteristics, such as an issuer’s practices toward managing legal and regulatory risks.

While Thornburg makes its own judgments about the ESG characteristics of each investment, Thornburg’s approach may be informed by third party data and other research tools, including consideration of the list of material ESG factors established by the Sustainability Accounting Standards Board.

Market observers differ in their perspectives and understanding of the importance of ESG factors to investment decisions. In its evaluation of potential investments, Thornburg may identify as significant certain ESG characteristics that are different from the characteristics that other investors may consider significant. Thornburg consequently may not consider the same ESG characteristics that other investors might consider in evaluating a potential investment. Similarly, Thornburg may assess the significance of ESG characteristics differently than some other investors, assigning either greater or lesser emphasis to a characteristic than another investor might assign.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Risks Affecting Investments in China – A significant portion of the Fund’s assets may be invested in companies exposed to China. Risks affecting investments in China include a potential downturn in the Chinese economy, reduced liquidity or increased price volatility in the Chinese securities markets as a result of trading suspensions affecting Chinese issuers or other factors, the potential that the Chinese government may expand restrictions on foreign investments or the repatriation of capital, and the implementation of new tariffs or other trade barriers by China or its trading partners. A lack of transparency respecting Chinese companies may also reduce the Fund’s ability to conduct diligence respecting those companies’ accounting and governance standards, which may in turn reduce the Fund’s ability to detect fraudulent practices that may adversely affect the companies’ stock prices.

Small and Mid-Cap Company Risk – Investments in small capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

ESG Investing Risk – Thornburg’s assessments of company ESG characteristics may result in decisions not to purchase, or to sell, investments which are otherwise consistent with the Fund’s investment goal and subsequently produce attractive investment performance, and Thornburg’s assessments of these characteristics may at times reduce the Fund’s exposure to market sectors or types of investments that produce positive investment performance. The application of ESG principles and the perceptions of the commitment of a given company to ESG principles vary among investors, analysts and other market observers. Consequently, Thornburg’s assessments respecting the ESG characteristics associated with any company may differ from the perceptions of other persons, including other mutual funds. Additionally, it may be difficult in certain instances for Thornburg to evaluate correctly a company’s commitment to positive ESG practices, and a failure to do so may result in investment in companies with practices that are not consistent with the Fund’s aspirations.

Real Estate Risk – The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Better World International Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares of the Fund have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the MSCI ACWI ex USA Net Total Return USD Index, net of withholding taxes on dividends, which is a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

22.85%

6/30/2020

Lowest Quarterly Results

(19.58)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Better World International Fund
1 Year
5 Years
Since Inception
Inception Date
Thornburg Better World International Fund - Class A 14.98% 13.34% 12.42% Oct. 01, 2015
Thornburg Better World International Fund - Class A | After Taxes on Distributions 9.89% 11.30% 10.35%  
Thornburg Better World International Fund - Class A | After Taxes on Distributions and Sales 9.95% 9.81% 9.05%  
Thornburg Better World International Fund - Class A | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 8.93%  
Thornburg Better World International Fund - Class C 18.36% 13.70% 12.56% Oct. 01, 2015
Thornburg Better World International Fund - Class C | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 8.93%  
Thornburg Better World International Fund - Class I 20.92% 15.19% 14.04% Oct. 01, 2015
Thornburg Better World International Fund - Class I | MSCI ACWI ex USA Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 8.93%  

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

The performance information shown above may include gains attributable to the Fund’s investments in shares of companies through initial public offerings (“IPOs”). There can be no assurance that the Fund will have continued access to profitable IPOs and, as the Fund’s assets grow, the impact of the Fund’s investment in IPOs on the performance of the Fund may decline.

Retail | Thornburg International Growth Fund
International Growth Fund
Investment Goal

The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg International Growth Fund
Thornburg International Growth Fund - Class A
Thornburg International Growth Fund - Class C
Thornburg International Growth Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg International Growth Fund
Thornburg International Growth Fund - Class A
Thornburg International Growth Fund - Class C
Thornburg International Growth Fund - Class I
Management Fees 0.80% 0.80% 0.80%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses [1] 0.21% 0.27% 0.19%
Total Annual Fund Operating Expenses 1.26% 2.07% 0.99%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes A, I and C would have been 0.22%, 0.27% and 0.20%, respectively.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg International Growth Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg International Growth Fund - Class A 573 832 1,110 1,904
Thornburg International Growth Fund - Class C 310 649 1,114 2,400
Thornburg International Growth Fund - Class I 101 315 547 1,213

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg International Growth Fund | Thornburg International Growth Fund - Class C | USD ($) 210 649 1,114 2,400
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 34.41% of the average value of its portfolio.

Principal Investment Strategies

The Fund expects to invest primarily in equity securities from issuers around the world (primarily common stocks) selected for their growth potential and, under normal market conditions, invests at least 75% of its assets in foreign securities or depositary receipts of foreign securities. However, the Fund may own a variety of securities, including domestic equity securities. The Fund may invest in developing countries.

The Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”) intends to invest in companies that it believes will have growing revenues and earnings. The Fund can invest in companies of any size, from larger, well-established companies to smaller, emerging growth companies.

Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

business model

industry growth potential

industry leadership

asset appreciation potential

potential size of business

price/earnings ratio

price/revenue ratio

PE/growth rate ratio

price/cash flow ratio

enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio

management strength

debt/capital ratio

The Fund typically makes equity investments in the following three types of companies:

Growth Industry Leaders: Companies in this category often have leadership positions in growing markets. In some cases these companies may have dominant market share. These companies tend to be larger and more established.

Consistent Growers: Companies in this category generally exhibit steady earnings or revenue growth, or both. These companies may have subscription or other recurring revenue profiles. Given their business models, these companies may outperform in weak markets.

Emerging Growth Companies: Companies often addressing a new market or carving out a niche in an existing market. Companies in this category may experience rapid growth, and tend to be smaller, earlier stage companies. These companies may exhibit high volatility.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

In conjunction with individual issuer analysis, Thornburg may identify and invest at times with a greater emphasis in industries or economic sectors it expects to experience growth. This approach may at times produce a greater emphasis on investment in certain industries or economic sectors, such as technology, financial services, healthcare or biotechnology. The Fund does not have a strategy to invest in particular industry or economic sectors, and its exposures to particular industries or economic sectors are expected to vary over time. Investment decisions are also based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for securities.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies, including smaller, earlier stage companies, may involve additional risks. These risks may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in International Growth Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total return for Class A shares has been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the MSCI ACWI ex USA Growth Net Total Return USD Index, a market capitalization weighted index which includes growth companies in developed and emerging markets throughout the world, excluding the United States. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

25.93%

6/30/2020

Lowest Quarterly Results

(17.74)%

12/31/2018

The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg International Growth Fund
1 Year
5 Years
10 Years
Thornburg International Growth Fund - Class A (8.76%) 11.39% 9.68%
Thornburg International Growth Fund - Class A | After Taxes on Distributions (10.17%) 10.52% 8.99%
Thornburg International Growth Fund - Class A | After Taxes on Distributions and Sales (4.14%) 8.93% 7.78%
Thornburg International Growth Fund - Class A | MSCI ACWI ex USA Growth Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%
Thornburg International Growth Fund - Class C (6.12%) 11.56% 9.34%
Thornburg International Growth Fund - Class C | MSCI ACWI ex USA Growth Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%
Thornburg International Growth Fund - Class I (4.20%) 12.80% 10.60%
Thornburg International Growth Fund - Class I | MSCI ACWI ex USA Growth Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Developing World Fund
Developing World Fund
Investment Goal

The Fund’s primary investment goal is long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charge applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Developing World Fund
Thornburg Developing World Fund Class A
Thornburg Developing World Fund Class C
Thornburg Developing World Fund Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Developing World Fund
Thornburg Developing World Fund Class A
Thornburg Developing World Fund Class C
Thornburg Developing World Fund Class I
Management Fees 0.94% 0.94% 0.94%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses 0.24% 0.25% 0.21%
Total Annual Fund Operating Expenses 1.43% 2.19% 1.15%
Fee Waiver/Expense Reimbursement (0.11%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.43% 2.19% 1.04%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.04%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Developing World Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Developing World Fund Class A 589 882 1,196 2,086
Thornburg Developing World Fund Class C 322 685 1,175 2,524
Thornburg Developing World Fund Class I 106 354 622 1,388

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Developing World Fund | Thornburg Developing World Fund Class C | USD ($) 222 685 1,175 2,524
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 61.50% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions the Fund invests at least 80% of its assets in equity securities of developing country issuers. A developing country issuer is a company or sovereign entity that is domiciled or otherwise tied economically to one or more developing countries. The Fund may invest in issuers of any size of capitalization, including small companies.

Currently, the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”) considers developing countries to include most Central and South American, African, Asian and Eastern European nations, including, but not limited to, Argentina, Austria, Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hong Kong, Hungary, India, Indonesia, Israel, South Korea, Malaysia, Mexico, Morocco, Nigeria, Pakistan, Peru, Philippines, Poland, Qatar, Romania, the Russian Federation, Slovenia, South Africa, Taiwan, Thailand, Turkey, Ukraine, the United Arab Emirates and Vietnam. Thornburg identifies what it considers to be developing countries based upon its own analysis of measures of industrialization, economic growth, population growth and other factors, and may also consider classifications by the World Bank, the International Finance Corporation, the United Nations and independent financial services firms that maintain indices of developing countries.

Thornburg considers a variety of factors to determine whether an investment is tied economically to one or more developing countries, including (i) whether or not a significant portion of the issuer’s revenues or assets are derived from or are located in developing countries, (ii) the primary trading market of the issuer’s securities, (iii) the locations of its principal offices or operations, (iv) the source of any governmental guarantees or other supports, (v) identification of the issuer’s securities within an index or other listing indicating its location in a particular developing country or region, and (vi) the extent to which the investment is otherwise exposed to the economic fortunes and risks of developing countries.

The Fund expects that under normal conditions its assets will be invested in issuers domiciled in or tied economically to a variety of different countries.

The Fund’s policy of investing at least 80% of its assets in developing country issuers may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Among the specific factors considered in identifying securities for inclusion in the Fund are domestic and international economic developments, outlooks for securities markets, the supply and demand for equity securities, and analysis of specific issuers. The Fund typically makes its equity investments in the following three types of issuers:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth, profitability, cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.


Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility. These risks may be more pronounced for the Fund’s investments in developing countries.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of an equity security may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protections.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Risks Affecting Investments in China – A significant portion of the Fund’s assets may be invested in companies exposed to China. Risks affecting investments in China include a potential downturn in the Chinese economy, reduced liquidity or increased price volatility in the Chinese securities markets as a result of trading suspensions affecting Chinese issuers or other factors, the potential that the Chinese government may expand restrictions on foreign investments or the repatriation of capital, and the implementation of new tariffs or other trade barriers by China or its trading partners. A lack of transparency respecting Chinese companies may also reduce the Fund’s ability to conduct diligence respecting those companies’ accounting and governance standards, which may in turn reduce the Fund’s ability to detect fraudulent practices that may adversely affect the companies’ stock prices.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Developing World Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the MSCI Emerging Markets Net Total Return USD Index, which represents a broad measure of equity market performance of emerging markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

21.64%

12/31/2020

Lowest Quarterly Results

(24.81)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Developing World Fund
1 Year
5 Years
10 Years
Thornburg Developing World Fund Class A (7.37%) 10.97% 7.23%
Thornburg Developing World Fund Class A | After Taxes on Distributions (7.37%) 10.75% 7.10%
Thornburg Developing World Fund Class A | After Taxes on Distributions and Sales (4.36%) 8.62% 5.80%
Thornburg Developing World Fund Class A | MSCI Emerging Markets Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) (2.54%) 9.87% 5.49%
Thornburg Developing World Fund Class C (4.72%) 11.14% 6.90%
Thornburg Developing World Fund Class C | MSCI Emerging Markets Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) (2.54%) 9.87% 5.49%
Thornburg Developing World Fund Class I (2.67%) 12.41% 8.17%
Thornburg Developing World Fund Class I | MSCI Emerging Markets Net Total Return USD Index (reflects no deduction for fees, expenses, or U.S. taxes) (2.54%) 9.87% 5.49%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Small/Mid Cap Core Fund
Small/Mid Cap Core Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.

The secondary, non-fundamental goal of the Fund is to seek some current income.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Small/Mid Cap Core Fund
Thornburg Small/Mid Cap Core Fund - Class A
Thornburg Small/Mid Cap Core Fund - Class C
Thornburg Small/Mid Cap Core Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Small/Mid Cap Core Fund
Thornburg Small/Mid Cap Core Fund - Class A
Thornburg Small/Mid Cap Core Fund - Class C
Thornburg Small/Mid Cap Core Fund - Class I
Management Fees 0.85% 0.85% 0.85%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses [1] 0.21% 0.28% 0.21%
Total Annual Fund Operating Expenses 1.31% 2.13% 1.06%
Fee Waiver/Expense Reimbursement (0.11%) [2]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.31% 2.13% 0.95%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes A, I and C would have been 0.23%, 0.30% and 0.23%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.95%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Small/Mid Cap Core Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Small/Mid Cap Core Fund - Class A 577 847 1,136 1,958
Thornburg Small/Mid Cap Core Fund - Class C 316 667 1,144 2,462
Thornburg Small/Mid Cap Core Fund - Class I 97 326 574 1,284

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Small/Mid Cap Core Fund | Thornburg Small/Mid Cap Core Fund - Class C | USD ($) 216 667 1,144 2,462
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 135.80% of the average value of its portfolio.

Principal Investment Strategies

Under normal conditions, the Fund invests at least 80% of its net assets in small- and mid-capitalization companies. The Fund currently defines small- and mid-capitalization companies to be those within the market capitalization range comprised by the Russell 2500 Index – Total Return. As of November 30, 2021, the market capitalization range of the Russell 2500 Index – Total Return was approximately $14 million to $33 billion. The market capitalization range of the Russell 2500 Index – Total Return changes over time and, as a result, the capitalization range of companies in which the Fund invests will also change. The Fund may change the definition of what constitutes “small- and mid-capitalization companies” without advance notice to shareholders.

The Fund expects to invest primarily in domestic common stocks. However, the Fund may own foreign common stocks which, in the opinion of the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), offer prospects for meeting the Fund’s investment goals.

With its core approach to stock selection, the Fund seeks to invest in a broadly diversified portfolio of companies the Fund categorizes as basic values, consistent earners, and emerging franchises, as described in more detail below. The relative proportions of securities invested in each of those categories will vary over time.

Thornburg primarily takes a bottom-up, fundamental view in determining the attractiveness of individual securities and in making investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

durable business model

industry growth potential

innovation driving the potential to disrupt entrenched competitors

intrinsic value appreciation potential

potential size of addressable market

management strength

leverage

return on invested capital

valuation metrics, including: price/earnings (“PE”) ratio; enterprise value/revenue ratio; PE/growth rate ratio, enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio; and free cash flow yield.

The Fund categorizes its investments in the following three categories:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth and profitability, and consistent cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its assets in small- and mid-capitalization companies may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, earlier stages of development and lack of well-established businesses, more limited access to markets

and financial resources, greater vulnerability to competition and market risks and fluctuations, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments. Relative to the stocks of large capitalization companies, the stocks of small- and mid-capitalization companies may be thinly traded and sales may result in higher transaction costs. Also, small- and mid-capitalization companies may perform poorly during times of economic stress.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in the Small/Mid Cap Core Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Russell 2500 Index—Total Return, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

18.89%

6/30/2020

Lowest Quarterly Results

(26.30)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown in the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Small/Mid Cap Core Fund
1 Year
5 Years
10 Years
Thornburg Small/Mid Cap Core Fund - Class A 8.70% 11.75% 12.70%
Thornburg Small/Mid Cap Core Fund - Class A | After Taxes on Distributions 0.39% 9.88% 11.71%
Thornburg Small/Mid Cap Core Fund - Class A | After Taxes on Distributions and Sales 8.70% 9.01% 10.44%
Thornburg Small/Mid Cap Core Fund - Class A | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%
Thornburg Small/Mid Cap Core Fund - Class C 12.10% 11.88% 12.34%
Thornburg Small/Mid Cap Core Fund - Class C | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%
Thornburg Small/Mid Cap Core Fund - Class I 14.18% 13.17% 13.64%
Thornburg Small/Mid Cap Core Fund - Class I | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

The performance information shown above may include gains attributable to the Fund’s investments in shares of companies through initial public offerings (“IPOs”). There can be no assurance that the Fund will have continued access to profitable IPOs and, as the Fund’s assets grow, the impact of the Fund’s investment in IPOs on the performance of the Fund may decline.

Retail | Thornburg Small/Mid Cap Growth Fund
Small/Mid Cap Growth Fund
Investment Goal

The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Small/Mid Cap Growth Fund
Thornburg Small/Mid Cap Growth Fund - Class A
Thornburg Small/Mid Cap Growth Fund - Class C
Thornburg Small/Mid Cap Growth Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Small/Mid Cap Growth Fund
Thornburg Small/Mid Cap Growth Fund - Class A
Thornburg Small/Mid Cap Growth Fund - Class C
Thornburg Small/Mid Cap Growth Fund - Class I
Management Fees 0.86% 0.86% 0.86%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses 0.20% 0.23% 0.18%
Total Annual Fund Operating Expenses 1.31% 2.09% 1.04%
Fee Waiver/Expense Reimbursement (0.09%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.31% 2.09% 0.95%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.95%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Small/Mid Cap Growth Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Small/Mid Cap Growth Fund - Class A 577 847 1,136 1,958
Thornburg Small/Mid Cap Growth Fund - Class C 312 655 1,124 2,421
Thornburg Small/Mid Cap Growth Fund - Class I 97 322 565 1,263

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Small/Mid Cap Growth Fund | Thornburg Small/Mid Cap Growth Fund - Class C | USD ($) 212 655 1,124 2,421
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 161.43% of the average value of its portfolio.

Principal Investment Strategies

Under normal conditions, the Fund invests at least 80% of its net assets in small- and mid-capitalization companies. The Fund currently defines small- and mid-capitalization companies to be those within the market capitalization range comprised by the Russell 2500 Growth Index – Total Return. As of November 30, 2021, the market capitalization range of the Russell 2500 Growth Index – Total Return was approximately $5 million to $33 billion. The market capitalization range of the Russell 2500 Growth Index – Total Return changes over time and, as a result, the capitalization range of companies in which the Fund invests will also change. The Fund may change the definition of what constitutes “small- and mid-capitalization companies” without advance notice to shareholders.

The Fund expects to invest primarily in domestic common stocks. However, the Fund may own foreign common stocks which, in the opinion of the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), offer prospects for meeting the Fund’s investment goal.

The Fund seeks to invest in a diversified portfolio of companies the Fund categorizes as consistent growers, disruptors, and emerging franchises, as described in more detail below. The relative proportions of securities invested in each of those categories will vary over time.

Thornburg primarily takes a bottom-up, fundamental view in determining the attractiveness of individual securities and in making investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

durable business model

industry growth potential

innovation driving the potential to disrupt entrenched competitors

intrinsic value appreciation potential

potential size of addressable market

management strength

leverage

return on invested capital

valuation metrics, including: price/earnings (“PE”) ratio; enterprise value/revenue ratio; PE/growth rate ratio, enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio; and free cash flow yield.

The Fund categorizes its equity investments in the following three categories:

Consistent Growers: Companies in this category generally exhibit steady earnings or revenue growth, or both. These companies may have subscription or other recurring revenue profiles. Given their business models, these companies may outperform in weak markets.

Disruptors: Companies which are at the early stages of growth; which usually possess highly innovative or differentiated products and services, but which may require substantial additional time or investment to capitalize on market opportunities and achieve profitability.

Emerging Franchises: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its assets in small- and mid-capitalization companies may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, earlier stages of development and lack of well-established businesses, more limited access to markets and financial resources, greater vulnerability to competition and market risks and fluctuations, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments. Relative to the stocks of large capitalization companies, the stocks of small- and mid-capitalization companies may be thinly traded and sales may result in higher transaction costs. Also, small- and mid-capitalization companies may perform poorly during times of economic stress.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Past Performance of the Fund

The following information provides some indication of the risks of investing in the Small/Mid Cap Growth Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Russell 2500 Growth Index—Total Return, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

30.93%

6/30/2020

Lowest Quarterly Results

(18.72)%

9/30/2011

The sales charge for Class A shares is not reflected in the returns shown in the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Small/Mid Cap Growth Fund
1 Year
5 Years
10 Years
Thornburg Small/Mid Cap Growth Fund - Class A (8.62%) 15.04% 13.36%
Thornburg Small/Mid Cap Growth Fund - Class A | After Taxes on Distributions (16.00%) 12.25% 11.98%
Thornburg Small/Mid Cap Growth Fund - Class A | After Taxes on Distributions and Sales 0.73% 12.05% 11.22%
Thornburg Small/Mid Cap Growth Fund - Class A | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%
Thornburg Small/Mid Cap Growth Fund - Class C (5.62%) 15.18% 13.01%
Thornburg Small/Mid Cap Growth Fund - Class C | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%
Thornburg Small/Mid Cap Growth Fund - Class I (3.99%) 16.51% 14.32%
Thornburg Small/Mid Cap Growth Fund - Class I | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Investment Income Builder Fund
Income Builder Fund
Investment Goal

The Fund’s primary investment goal is to provide a level of current income which exceeds the average yield on U.S. stocks generally, and which will generally grow, subject to periodic fluctuations, over the years on a per share basis.

The Fund’s secondary investment goal is long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Investment Income Builder Fund
Thornburg Investment Income Builder Fund - Class A
Thornburg Investment Income Builder Fund - Class C
Thornburg Investment Income Builder Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Investment Income Builder Fund
Thornburg Investment Income Builder Fund - Class A
Thornburg Investment Income Builder Fund - Class C
Thornburg Investment Income Builder Fund - Class I
Management Fees 0.70% 0.70% 0.70%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses [1] 0.18% 0.20% 0.19%
Acquired Fund Fees and Expenses 0.05% 0.05% 0.05%
Total Annual Fund Operating Expenses [2] 1.18% 1.95% 0.94%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes A, I and C would have been 0.31%, 0.33% and 0.32%, respectively.
[2] The figures for Total Annual Fund Operating Expenses in this table have been recalculated to add amounts for “Acquired Fund Fees and Expenses,” in accordance with regulatory rules. Acquired Fund Fees and Expenses vary with changes in the amount of the Fund’s investments in investment companies and other factors. Please see the disclosure under the caption “Explanation of Acquired Fund Fees and Expenses” for a further explanation.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example - Retail - Thornburg Investment Income Builder Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Investment Income Builder Fund - Class A 565 808 1,070 1,817
Thornburg Investment Income Builder Fund - Class C 298 612 1,052 2,275
Thornburg Investment Income Builder Fund - Class I 96 300 520 1,155

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Investment Income Builder Fund | Thornburg Investment Income Builder Fund - Class C | USD ($) 198 612 1,052 2,275
Explanation of Acquired Fund Fees and Expenses.

“Acquired Fund Fees and Expenses” shown in the Annual Fund Operating Expenses table are expenses incurred indirectly by other investment companies, such as business development companies, in which the Fund may hold shares. These operating expenses are similar to the expenses paid by other businesses owned by the Fund, are not direct costs paid by Fund shareholders, and are not used to calculate the Fund’s net asset value. These expenses have no impact on the costs associated with Fund operations. Regulatory rules require that the Acquired Fund Fees and Expenses be added to the actual operating expenses of the Fund, and that the total be shown in the bottom line of the Annual Fund Operating Expenses table. Please see the expense figures shown in the Financial Highlights for the Fund, at pages 174 –175, for a clearer picture of the Fund’s actual operating costs.

Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18.99% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goals by investing in a broad range of income producing securities, primarily including stocks and bonds, as described below. The Fund will under normal conditions invest at least 80% of its assets in income-producing securities, and at least 50% of its assets in common stocks.

The Fund may invest in any stock or other equity security which the investment advisor believes may assist the Fund in pursuing its investment goals (including smaller companies with market capitalization of less than $500 million and companies in developing countries), including preferred stock and publicly traded real estate investment trusts. The Fund expects that equity investments in the Fund’s portfolio normally will be weighted in favor of companies which pay dividends or other current income.

The Fund may invest in debt obligations of any kind, including corporate bonds and other obligations, mortgage- and other asset-backed securities and government obligations. The Fund may purchase debt obligations of any maturity and of any credit quality, including “high yield” or “junk” bonds. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics, such as convertible bonds.

The Fund may invest a significant portion of its assets in securities of issuers domiciled in or economically tied to countries outside the United States, including developing countries.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or otherwise to respond to market conditions.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments in debt obligations may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Real Estate Risk – The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Income Builder Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to a Blended Benchmark comprised of 25% Bloomberg Barclays US Aggregate Bond Total Return Value USD, which represents a broad measure of bond market performance, and 75% MSCI World Net Total Return USD Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

15.96%

12/31/2020

Lowest Quarterly Results

(25.98)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Investment Income Builder Fund
1 Year
5 Years
10 Years
Thornburg Investment Income Builder Fund - Class A 14.62% 7.96% 7.50%
Thornburg Investment Income Builder Fund - Class A | After Taxes on Distributions 12.21% 5.95% 5.48%
Thornburg Investment Income Builder Fund - Class A | After Taxes on Distributions and Sales 8.58% 5.23% 4.93%
Thornburg Investment Income Builder Fund - Class A | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%
Thornburg Investment Income Builder Fund - Class C 18.10% 8.16% 7.22%
Thornburg Investment Income Builder Fund - Class C | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%
Thornburg Investment Income Builder Fund - Class I 20.29% 9.25% 8.31%
Thornburg Investment Income Builder Fund - Class I | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Summit Fund
Summit Fund
Investment Goal

The Fund seeks to grow real wealth over time.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Summit Fund
Thornburg Summit Fund - Class A
Thornburg Summit Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Summit Fund
Thornburg Summit Fund - Class A
Thornburg Summit Fund - Class I
Management Fees 0.75% 0.75%
Distribution and Service (12b-1) Fees 0.25% none
Dividend Expenses on Short Sales [1] 0.02% 0.02%
Borrowing Costs on Short Sales and Interest Expenses [1] none none
Other Expenses [1] 0.43% 0.43%
Acquired Fund Fees and Expenses 0.02% 0.02%
Total Annual Fund Operating Expenses 1.47% 1.22%
Fee Waiver/Expense Reimbursement [2] (0.19%) (0.19%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.28% 1.03%
[1] These expenses reflect the expenses the Fund will incur to sell securities short and interest expense on borrowed funds. These expenses are required to be treated as a Fund expense for accounting purposes and are not payable to the Fund’s investment advisor.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) incurred by the Fund so that actual Class A and Class I expenses do not exceed 1.24% and 0.99%, respectively, not including the effects of expenses relating to the Fund’s short sales, and interest expenses. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023 unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if, after taking the recoupment into account, the Fund’s actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year) your costs would be:

Expense Example - Retail - Thornburg Summit Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Summit Fund - Class A 575 876 1,199 2,113
Thornburg Summit Fund - Class I 105 368 652 1,461
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 155.26% of the average value of its portfolio.

Principal Investment Strategies

The Fund seeks to grow real wealth over time. “Real wealth” for this purpose is a mix of capital appreciation and current income that is intended to exceed the rate of inflation. While the Fund seeks to achieve its goal over a variety of different market environments by selecting investments from a range of asset classes, the value of an investment in the Fund will fluctuate and the Fund may not achieve its goal in every environment or in all environments. Under normal conditions the Fund’s investments are expected to emphasize long positions in equity securities and fixed income obligations, though the Fund may also invest a significant amount of its assets in short positions in equity securities and fixed income obligations, in commodities-related investments, in derivative instruments, in currencies, and in cash or cash equivalents. There are no specific percentage limitations on the amount of the Fund’s portfolio that may be invested in a particular asset class, and the proportions of the Fund’s assets that are invested in the respective asset classes are expected to vary over time and from time to time depending upon Thornburg’s perceptions of which types of investments represent better values and opportunities to achieve the Fund’s investment goal.

With respect to its equity investments, the Fund may invest in any stock or equity security, including common stocks, preferred stocks, convertible securities, warrants, depositary receipts, publicly traded real estate investment trusts, and shares in exchange traded funds. The Fund may invest in companies of any size. The Fund’s portfolio may include investments in United States issuers and the securities of issuers domiciled outside the United States, including developing countries. The relative proportions of the Fund’s U.S. and foreign investments will vary over time depending upon Thornburg’s view of specific investment opportunities and macroeconomic factors.

With respect to its fixed income investments, the Fund expects that under normal market conditions its investments will include the following types of obligations, which may be of any quality and of any maturity:

bonds and other debt obligations issued by domestic and foreign companies of any size (including lower-rated “high yield” or “junk” bonds);

mortgage-backed securities and other asset-backed securities;

convertible debt obligations;

obligations issued by foreign governments (including developing countries);

collateralized mortgage obligations (“CMOs”), collateralized debt obligations (“CDOs”), collateralized bond obligations (“CBOs”), and collateralized loan obligations (“CLOs”);

obligations of the U.S. government and its agencies and sponsored enterprises;

zero coupon bonds and “stripped” securities (including both income only and principal only securities); and

taxable municipal obligations and participations in municipal obligations.

The Fund’s investments may include both long and short positions. A short sale involves the sale by the Fund of a security that the Fund does not own. The Fund borrows the security that it intends to sell from a broker or other institution, and at a later date the Fund completes the short sale by purchasing that same security on the open market and delivering it to the lending institution. The Fund may also seek to achieve short exposure to an investment through the use of derivative instruments, Allocating the Fund’s portfolio among long and short positions is intended to permit the Fund to pursue its investment goal with lower volatility relative to broad-based securities market indices. While the Fund expects under normal conditions to invest a larger portion of its portfolio in long positions than short positions, the relative proportions of long and short equity investments will vary, and its short positions may represent a significant portion of the Fund’s portfolio during some periods.

With respect to its commodities-related investments, the Fund may invest in exchange traded funds or in other, similar investment vehicles that invest in commodities, and the Fund may invest in commodity-linked derivative instruments whose value is based on the value of an underlying commodity or commodity index, such as commodity futures contracts, commodity forward contracts, and commodity options contracts. The Fund may also seek to obtain exposure to the investment returns of commodities markets by investing in equity and debt securities of companies that operate commodities-based businesses.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for equity and debt securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such security prior to its scheduled maturity to enhance income or reduce loss or to change the portfolio’s average maturity, and the Fund may dispose of any of its investments if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund may also purchase or sell futures contracts or purchase or sell interest rate swaps or credit default swaps to hedge against a decline in the value of the Fund’s other investments, to obtain investment exposure to a particular asset class, or to establish a short position with respect to an investment.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk The Fund is an actively managed portfolio, and the value of the Fund may be reduced or the Fund may otherwise be unsuccessful in pursuing its investment goal if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility. This effect is typically more pronounced for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments. Additionally, because the Fund has to accrue income on zero coupon bonds on a current basis even though the Fund does not receive the income from those bonds currently in cash, zero coupon bonds subject the Fund to the risk of having to generate cash from other sources (including through the sale of portfolio securities) in order to make required distributions of the income accrued from its investments in zero coupon bonds.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected.

These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk Investments in securities of foreign issuers and in depositary receipts may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Developing Country Risk The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Small and Mid-Cap Company Risk Investments in small capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Short Sale Risk A short sale involves the sale by the Fund of a security that the Fund has borrowed, but does not own, in anticipation of purchasing that same security at a lower price in the future in order to close the short position. If the value of the borrowed security increases between the date the Fund enters into the short sale and the date that the Fund buys that security to cover its short position, the Fund may experience a loss.

Credit Risk If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk. Debt obligations backed by so-called “subprime” mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

High Yield Risk Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Interest Rate Risk When interest rates increase, the value of the Fund’s investments in debt obligations may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. This effect is also typically more pronounced for zero coupon bonds and mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends, if any, may decline.

 

Prepayment and Extension Risk When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Liquidity Risk Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries. Additionally, the market for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds) and debt obligations backed by so-called “subprime” mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Inflation Risk – Although the Fund seeks to generate capital appreciation and current income that exceeds the rate of inflation over a variety of different market environments, there is no guarantee that the Fund will be able to do so at all times. If at any time the rate of inflation exceeds Thornburg’s expectations, or if for other reasons the Fund’s portfolio is unsuccessful in producing a mix of capital appreciation and current income that exceeds the rate of inflation, the Fund may not achieve its goal.

Structured Products Risk Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in CMOs, CDOs and CLOS, involve risks associated with the underlying assets (e.g., the risks of default by mortgagors whose mortgages are included in a mortgage-backed security or CMO), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, prepayment and extension risk, and the risk that the securities will be less liquid than other Fund investments.

Commodities-Related Investment Risk Investments that expose the Fund to the commodities market, such as commodity-linked derivatives instruments or exchange traded funds or other investment vehicles that invest in commodities, may subject the Fund to greater volatility than investments in other securities. The value of a commodity-related investment may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, risks affecting derivatives when used to obtain commodities exposure, or factors affecting a particular industry or commodity.

Real Estate Risk The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

Derivatives Risk The Fund’s investments in futures, interest rate swaps, and credit default swaps involve the risks associated with the securities or other assets underlying those derivatives, including the risk of changes in the value of the underlying assets between the date that the Fund enters into the derivatives transaction and the date that the Fund closes out that transaction. The Fund’s investments in futures, interest rate swaps, and credit default swaps also involve the risk that the other party to the transaction will be unable or unwilling to perform its obligations to the Fund, that the Fund will be unable to sell or close its positions in such derivatives or will be delayed in doing so, and that the Fund will have difficulty valuing such derivatives.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Summit Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class I shares of the Fund have been different in each full year shown. The average annual total return figures compare Class I share performance to the Blended Benchmark, comprised of 60% MSCI All Country (AC) World Index, which represents a broad measure of both domestic and foreign equity market performance, and 40% Bloomberg Barclays Global Aggregate Bond Index, which

provides a broad-based measure of the global investment-grade fixed-rate debt markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class I Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

17.10%

6/30/2020

Lowest Quarterly Results

(9.27)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Summit Fund - Thornburg Summit Fund - Class I
1 Year
Since Inception
Inception Date
Performance Measure Domain 14.64% 18.23% Mar. 01, 2019
After Taxes on Distributions 7.51% 14.44%  
After Taxes on Distributions and Sales 9.16% 12.74%  
Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 8.78% 11.88%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Retail | Thornburg Limited Term U.S. Government Fund
Limited Term U.S. Government Fund
Investment Goal

The primary goal of Limited Term U.S. Government Fund is to provide as high a level of current income as is consistent, in the view of the Fund’s investment advisor, with safety of capital.

As a secondary goal, the Fund seeks to reduce changes in its share price compared to longer term portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Limited Term U.S. Government Fund
Thornburg Limited Term U.S. Government Fund - Class A
Thornburg Limited Term U.S. Government Fund - Class C
Thornburg Limited Term U.S. Government Fund - Class C2
Thornburg Limited Term U.S. Government Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.50% [2] 0.65% [2] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C and Class C2 shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Limited Term U.S. Government Fund
Thornburg Limited Term U.S. Government Fund - Class A
Thornburg Limited Term U.S. Government Fund - Class C
Thornburg Limited Term U.S. Government Fund - Class C2
Thornburg Limited Term U.S. Government Fund - Class I
Management Fees 0.37% 0.37% 0.37% 0.37%
Distribution and Service (12b-1) Fees 0.25% 0.50% 0.65% none
Other Expenses 0.25% 0.37% 2.35% 0.24%
Total Annual Fund Operating Expenses 0.87% 1.24% 3.37% 0.61%
Fee Waiver/Expense Reimbursement (2.13%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.87% 1.24% 1.24% 0.61%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class C2 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.24%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example - Retail - Thornburg Limited Term U.S. Government Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Limited Term U.S. Government Fund - Class A 312 496 696 1,273
Thornburg Limited Term U.S. Government Fund - Class C 176 393 681 1,500
Thornburg Limited Term U.S. Government Fund - Class C2 191 837 1,571 3,514
Thornburg Limited Term U.S. Government Fund - Class I 62 195 340 762

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption - Retail - Thornburg Limited Term U.S. Government Fund - USD ($)
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Thornburg Limited Term U.S. Government Fund - Class C 126 393 681 1,500
Thornburg Limited Term U.S. Government Fund - Class C2 126 837 1,571 3,514
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 9.50% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio in pursuing the Fund’s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund’s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security before its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or to otherwise respond to market conditions.

Limited Term U.S. Government Fund invests at least 80% of its assets in U.S. Government Securities. For this purpose, “U.S. Government Securities” means:

Securities backed by the full faith and credit of the U.S. government, including direct obligations of the U.S. Treasury (such as U.S. Treasury Bonds) and obligations of U.S. government agencies and instrumentalities which are guaranteed by the U.S. Treasury (such as “Ginnie Mae” mortgage-backed certificates issued by the Government National Mortgage Association).

Securities issued or guaranteed by U.S. government agencies, instrumentalities or sponsored enterprises, but which are not backed by the full faith and credit of the U.S. government. These securities include mortgage-backed certificates, collateralized mortgage obligations (“CMOs”), and debentures issued by “Freddie Mac” (Federal Home Loan Mortgage Corporation) and “Fannie Mae” (Federal National Mortgage Association).

U.S. Government Securities include for this purpose repurchase agreements secured by the securities described above, and participations having economic characteristics similar to those securities. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants.

Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund’s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund’s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed securities.

Credit Risk – All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund’s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government-sponsored enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund are rated “Aaa” by Moody’s Investors Services or “AA+” by S&P Global Ratings. Ratings agencies may reduce the ratings of any securities in the future.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage-backed securities and in CMOs, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or CMO), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term U.S. Government Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C, Class C2 and Class I share performance to the Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

1.93%

6/30/2011

Lowest Quarterly Results

(1.68)%

3/31/2021

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Limited Term U.S. Government Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Limited Term U.S. Government Fund - Class A (4.06%) 1.07% 0.90%    
Thornburg Limited Term U.S. Government Fund - Class A | After Taxes on Distributions (4.52%) 0.44% 0.19%    
Thornburg Limited Term U.S. Government Fund - Class A | After Taxes on Distributions and Sales (2.40%) 0.54% 0.38%    
Thornburg Limited Term U.S. Government Fund - Class A | Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32% 1.68%    
Thornburg Limited Term U.S. Government Fund - Class C (2.67%) 1.04% 0.75%    
Thornburg Limited Term U.S. Government Fund - Class C | Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32% 1.68%    
Thornburg Limited Term U.S. Government Fund - Class C2 (2.82%)     (1.77%) Oct. 01, 2020
Thornburg Limited Term U.S. Government Fund - Class C2 | Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.69%)     (1.53%)  
Thornburg Limited Term U.S. Government Fund - Class I (1.58%) 1.67% 1.36%    
Thornburg Limited Term U.S. Government Fund - Class I | Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32% 1.68%    

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Limited Term Income Fund
Limited Term Income Fund
Investment Goal

The primary goal of Limited Term Income Fund is to provide as high a level of current income as is consistent, in the view of the Fund’s investment advisor, with safety of capital.

As a secondary goal, the Fund seeks to reduce changes in its share prices compared to longer term portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Limited Term Income Fund
Thornburg Limited Term Income Fund - Class A
Thornburg Limited Term Income Fund - Class C
Thornburg Limited Term Income Fund - Class C2
Thornburg Limited Term Income Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.50% [2] 0.65% [2] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C and Class C2 shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Limited Term Income Fund
Thornburg Limited Term Income Fund - Class A
Thornburg Limited Term Income Fund - Class C
Thornburg Limited Term Income Fund - Class C2
Thornburg Limited Term Income Fund - Class I
Management Fees 0.31% 0.31% 0.31% 0.31%
Distribution and Service (12b-1) Fees 0.25% 0.50% 0.65% none
Other Expenses 0.21% 0.18% 0.36% 0.19%
Total Annual Fund Operating Expenses 0.77% 0.99% 1.32% 0.50%
Fee Waiver/Expense Reimbursement (0.08%) [1] (0.01%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.77% 0.99% 1.24% 0.49%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class C2 and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.24% and 0.49%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example - Retail - Thornburg Limited Term Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Limited Term Income Fund - Class A 302 465 643 1,158
Thornburg Limited Term Income Fund - Class C 151 315 547 1,213
Thornburg Limited Term Income Fund - Class C2 191 410 716 1,583
Thornburg Limited Term Income Fund - Class I 50 159 279 627

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption - Retail - Thornburg Limited Term Income Fund - USD ($)
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Thornburg Limited Term Income Fund - Class C 101 315 547 1,213
Thornburg Limited Term Income Fund - Class C2 126 410 716 1,583
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 33.37% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio in pursuing the Fund’s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund’s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or to otherwise respond to current market conditions.

The Fund invests at least 65% of its net assets in (i) obligations of the U.S. government, its agencies and instrumentalities, and (ii) debt obligations rated at the time of purchase in one of the three highest principal long term rating categories of S&P Global Ratings (AAA, AA or A) or Moody’s Investors Services, Inc. (Aaa, Aa or A), or the equivalent three highest short term ratings of those ratings agencies, or, if no credit rating is available, judged to be of comparable quality as determined by Thornburg. The Fund will not invest in any debt obligation rated at the time of purchase lower than BBB by S&P, Baa by Moody’s, of the equivalent short term ratings of those ratings agencies, or, if no credit rating is available, judged to be of comparable quality as determined by Thornburg. The Fund may purchase corporate debt obligations, municipal securities, and commercial paper and bankers’ acceptances, and the Fund may also purchase securities backed by an underlying pool of debt obligations, including mortgage-backed securities, asset-backed securities, collateralized mortgage obligations, and collateralized debt obligations (sometimes referred to collectively as “structured products”). The Fund may purchase foreign securities of the same types and quality as the domestic securities it purchases when Thornburg believes these investments are consistent with the Fund’s objectives.

Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than five years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example,

an obligation with a duration of 5 would be expected to change in price by approximately 5% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund’s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund’s investment in mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Credit Risk – All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund’s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government sponsored enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund, are rated “Aaa” by Moody’s Investors Services or “AA+” by S&P Global Ratings. Ratings agencies may reduce the ratings of any securities in the future. Lower-rated or unrated obligations in which the Fund is permitted to invest may have, or may be perceived to have, greater risk of default and ratings downgrades.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.

Risks Affecting Specific Issuers – The value of a debt obligation may decline in response to developments affecting the specific issuer of the obligation, even if other issuers or the overall economy are unaffected. These developments may include

a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C, Class C2 and Class I share performance to the Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

5.71%

6/30/2020

Lowest Quarterly Results

(2.06)%

6/30/2013

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Limited Term Income Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Limited Term Income Fund - Class A (3.28%) 2.63% 2.74%    
Thornburg Limited Term Income Fund - Class A | After Taxes on Distributions (3.79%) 1.66% 1.71%    
Thornburg Limited Term Income Fund - Class A | After Taxes on Distributions and Sales (1.94%) 1.60% 1.66%    
Thornburg Limited Term Income Fund - Class A | Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91% 2.38%    
Thornburg Limited Term Income Fund - Class C (1.78%) 2.73% 2.66%    
Thornburg Limited Term Income Fund - Class C | Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91% 2.38%    
Thornburg Limited Term Income Fund - Class C2 (2.18%)     (0.61%) Oct. 01, 2020
Thornburg Limited Term Income Fund - Class C2 | Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.44%)     (0.77%)  
Thornburg Limited Term Income Fund - Class I (0.80%) 3.25% 3.23%    
Thornburg Limited Term Income Fund - Class I | Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91% 2.38%    

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Ultra Short Income Fund
Ultra Short Income Fund
Investment Goal

The Fund seeks current income, consistent with preservation of capital.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Ultra Short Income Fund
Thornburg Ultra Short Income Fund Class A
Thornburg Ultra Short Income Fund Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Ultra Short Income Fund
Thornburg Ultra Short Income Fund Class A
Thornburg Ultra Short Income Fund Class I
Management Fees 0.25% 0.25%
Distribution and Service (12b-1) Fees 0.20% none
Other Expenses 0.93% 0.51%
Total Annual Fund Operating Expenses 1.38% 0.76%
Fee Waiver/Expense Reimbursement [1] (0.88%) (0.46%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.50% 0.30%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.50% and 0.30%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year) your costs would be:

Expense Example - Retail - Thornburg Ultra Short Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Ultra Short Income Fund Class A 275 567 881 1,770
Thornburg Ultra Short Income Fund Class I 31 197 377 899
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 37.51% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management Inc. (“Thornburg”) actively manages the Fund’s holdings in pursuing the Fund’s investment goal. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund’s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, or to otherwise respond to current market conditions.

Under normal conditions, the Fund invests at least 80% of its net assets in (i) obligations of the U.S. government, its agencies and instrumentalities, and (ii) debt obligations rated at the time of purchase in one of the four highest ratings of S&P Global Ratings (AAA, AA, A, or BBB) or Moody’s Investors Services, Inc. (Aaa, Aa, A, or Baa) or, if no credit rating is available, judged to be of comparable quality by Thornburg. The Fund may purchase corporate debt, municipal securities, and short-term commercial paper and bankers’ acceptances, and the Fund may also purchase securities backed by an underlying pool of debt obligations, including mortgage-backed securities, asset-backed securities, collateralized mortgage obligations, and collateralized debt obligations (sometimes referred to collectively as “structured products”). The Fund may purchase foreign securities of the same types and quality as the domestic securities it purchases when Thornburg anticipates foreign securities offer more investment potential. The Fund may invest in debt obligations which are rated by S&P Global Ratings or Moody’s Investors Services, Inc. at the time of purchase as below investment grade (commonly referred to as “junk” or “high yield” bonds) or, if no credit rating is available, are judged to be of comparable quality by Thornburg, but such investments will be less than 20% of the Fund’s net assets under normal conditions.

The Fund may also purchase or sell futures contracts or purchase or sell interest rate swaps or credit default swaps to hedge against a decline in the value of the Fund’s other investments or to manage portfolio duration.

Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer durations given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value compared to longer duration fixed income portfolios by maintaining a portfolio of investments with a dollar-weighted average duration of normally no more than one half (0.5) of a year. Duration is a measure of estimated sensitivity to interest rate changes, and a debt obligation or a portfolio of obligations with a higher duration will typically be more sensitive to interest rate changes than an obligation or a portfolio with a lower duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 0.5 would be expected to change in price by approximately 0.5% in response to a 1% change in interest rates. There is no limitation on the duration or maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection, and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund’s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The Fund seeks higher income than is typically available, across market cycles, from investment in a money market fund. Consequently, if your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Credit Risk – All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund’s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government sponsored enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the U.S. government, and the securities of U.S. government agencies, instrumentalities and enterprises that may be purchased by the Fund are rated “Aaa” by Moody’s Investors Services or “AA+” by S&P Global Ratings. Ratings agencies may reduce the ratings of any securities in the future.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.

Risks Affecting Specific Issuers – The value of a debt obligation may decline in response to developments affecting the specific issuer of the obligation, even if other issuers or the overall economy are unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes, or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Liquidity Risk – Due to lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Derivatives Risk – The Fund’s investments in futures, interest rate swaps, and credit default swaps involve the risks associated with the securities or other assets underlying those derivatives, including the risk of changes in the value of the underlying assets between the date that the Fund enters into the derivatives transaction and the date that the Fund closes out that transaction. The Fund’s investments in futures, interest rate swaps, and credit default swaps also involve the risk that the other party to the transaction will be unable or unwilling to perform its obligations to the Fund, that the Fund will be unable to sell or close its positions in such derivatives or will be delayed in doing so, and that the Fund will have difficulty valuing such derivatives.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Ultra Short Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A and Class I share performance to the ICE BofAML U.S. Treasury Bill Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

3.80%

6/30/2020

Lowest Quarterly Results

(1.66)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Ultra Short Income Fund
1 Year
5 Years
Since Inception
Inception Date
Thornburg Ultra Short Income Fund Class A (2.14%) 1.61% 1.42% Dec. 30, 2013
Thornburg Ultra Short Income Fund Class A | After Taxes on Distributions (2.67%) 0.82% 0.78%  
Thornburg Ultra Short Income Fund Class A | After Taxes on Distributions and Sales (1.27%) 0.89% 0.81%  
Thornburg Ultra Short Income Fund Class A | ICE BofAML US Treasury Bill Index (reflects no deduction for fees, expenses, or taxes) 0.05% 1.16% 0.79%  
Thornburg Ultra Short Income Fund Class I 0.32% 2.09% 1.80% Dec. 30, 2013
Thornburg Ultra Short Income Fund Class I | ICE BofAML US Treasury Bill Index (reflects no deduction for fees, expenses, or taxes) 0.05% 1.16% 0.79%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation, and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Strategic Income Fund
Strategic Income Fund
Investment Goal

The Fund’s primary investment goal is to seek a high level of current income.

The Fund’s secondary investment goal is some long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Strategic Income Fund
Thornburg Strategic Income Fund - Class A
Thornburg Strategic Income Fund - Class C
Thornburg Strategic Income Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 4.50% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 1.00% [2] none
[1] Up to a 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Strategic Income Fund
Thornburg Strategic Income Fund - Class A
Thornburg Strategic Income Fund - Class C
Thornburg Strategic Income Fund - Class I
Management Fees 0.60% 0.60% 0.60%
Distribution and Service (12b-1) Fees 0.25% 1.00% none
Other Expenses 0.20% 0.23% 0.21%
Total Annual Fund Operating Expenses 1.05% 1.83% 0.81%
Fee Waiver/Expense Reimbursement (0.03%) [1] (0.21%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.05% 1.80% 0.60%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class C, and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.80%, and 0.60%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Strategic Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Strategic Income Fund - Class A 552 769 1,003 1,675
Thornburg Strategic Income Fund - Class C 283 573 988 2,145
Thornburg Strategic Income Fund - Class I 61 238 429 982

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Strategic Income Fund | Thornburg Strategic Income Fund - Class C | USD ($) 183 573 988 2,145
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 28.55% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goals by investing in a broad range of income-producing investments from throughout the world, primarily including debt obligations. The Fund expects, under normal conditions, to invest a majority of its assets in the debt obligations described below.

The Fund may invest in debt obligations of any kind, of any quality, and of any maturity. The Fund expects, under normal conditions, to select a majority of its investments from among the following types of debt obligations:

bonds and other debt obligations issued by domestic and foreign companies of any size (including lower-rated “high yield” or “junk” bonds)

mortgage-backed securities and other asset-backed securities, including commercial mortgage-backed securities

convertible debt obligations

obligations issued by foreign governments (including developing countries)

collateralized mortgage obligations (“CMOs”), collateralized debt obligations (“CDOs”), collateralized bond obligations (“CBOs”), and collateralized loan obligations (“CLOs”)

obligations of the U.S. government and its agencies and sponsored enterprises

structured notes

zero coupon bonds and “stripped” securities

taxable municipal obligations and participations in municipal obligations

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt securities, and analysis of specific issuers.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund’s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. Debt obligations backed by so-called “subprime” mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments. The market value of any zero coupon bonds or “stripped” securities that the Fund may purchase will typically be more volatile than the value of a comparable, interest-paying bond. Additionally, zero coupon bonds and “stripped” securities are subject to the risk that the Fund may have to recognize income on its investment and make distributions to shareholders before it has received any cash payments on its investment.

Risks Affecting Specific Issuers – The value of a debt obligation may decline in response to developments affecting the specific issuer of the obligation or security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. The market for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds) and debt obligations backed by so-called “subprime” mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Foreign Investment Risk – Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

 

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total return for Class A shares has been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I performance to the Bloomberg Barclays US Universal Total Return Index Value Unhedged, a broad measure of market performance, and to a Blended Benchmark, comprised of 80% Bloomberg Barclays US Aggregate Bond Total Return Value USD, which represents a broad measure of bond market performance, and 20% MSCI World Net Total Return USD Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

7.98%

6/30/2020

Lowest Quarterly Results

(5.71)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Strategic Income Fund
1 Year
5 Years
10 Years
Thornburg Strategic Income Fund - Class A (2.21%) 3.83% 4.55%
Thornburg Strategic Income Fund - Class A | After Taxes on Distributions (3.70%) 2.40% 2.72%
Thornburg Strategic Income Fund - Class A | After Taxes on Distributions and Sales (1.31%) 2.30% 2.69%
Thornburg Strategic Income Fund - Class A | Bloomberg Barclays US Universal Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.31%
Thornburg Strategic Income Fund - Class A | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.95%
Thornburg Strategic Income Fund - Class C 0.64% 4.01% 4.35%
Thornburg Strategic Income Fund - Class C | Bloomberg Barclays US Universal Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.31%
Thornburg Strategic Income Fund - Class C | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.95%
Thornburg Strategic Income Fund - Class I 2.78% 5.17% 5.39%
Thornburg Strategic Income Fund - Class I | Bloomberg Barclays US Universal Total Return Index Value Unhedged (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.31%
Thornburg Strategic Income Fund - Class I | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.95%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Short Duration Municipal Fund
Short Duration Municipal Fund
Investment Goal

The Fund seeks current income exempt from federal income tax, consistent with preservation of capital.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Short Duration Municipal Fund
Thornburg Short Duration Municipal Fund Class A
Thornburg Short Duration Municipal Fund Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Short Duration Municipal Fund
Thornburg Short Duration Municipal Fund Class A
Thornburg Short Duration Municipal Fund Class I
Management Fees 0.40% 0.40%
Distribution and Service (12b-1) Fees 0.20% none
Other Expenses 0.38% 0.25%
Total Annual Fund Operating Expenses 0.98% 0.65%
Fee Waiver/Expense Reimbursement [1] (0.28%) (0.15%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.70% 0.50%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.70% and 0.50%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year) your costs would be:

Expense Example - Retail - Thornburg Short Duration Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Short Duration Municipal Fund Class A 295 503 728 1,374
Thornburg Short Duration Municipal Fund Class I 51 193 347 796
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 34.71% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by states and state agencies, local governments and their agencies and by United States territories and possessions. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer durations given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value compared to longer duration fixed income portfolios by maintaining a portfolio of investments with a dollar-weighted average duration of normally no more than three years. Duration is a measure of estimated sensitivity to interest rate changes, and a debt obligation or a portfolio of obligations with a higher duration will typically be more sensitive to interest rate changes than an obligation or a portfolio with a lower duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 3 would be expected to change in price by approximately 3% in response to a 1% change in interest rates. During temporary periods the Fund’s average duration and average portfolio maturity may be further reduced for defensive purposes. There is no limitation on the duration or maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

The Fund normally invests 100% of its assets in municipal obligations, the income from which is exempt from the regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The Fund seeks higher income than is typically available, across market cycles, from investment in a money market fund. Consequently, if your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and any dividends paid by the Fund may be reduced. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Short Duration Municipal Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A and Class I share performance to the ICE BofAML 1-3 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter ended

Highest Quarterly Results

0.92%

6/30/2020

Lowest Quarterly Results

(0.51)%

3/31/2020

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Short Duration Municipal Fund
1 Year
5 Years
Since Inception
Inception Date
Thornburg Short Duration Municipal Fund Class A (2.46%) 0.54% 0.40% Dec. 30, 2013
Thornburg Short Duration Municipal Fund Class A | After Taxes on Distributions (2.46%) 0.54% 0.40%  
Thornburg Short Duration Municipal Fund Class A | After Taxes on Distributions and Sales (1.36%) 0.61% 0.45%  
Thornburg Short Duration Municipal Fund Class A | ICE BofAML 1-3 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.34% 1.62% 1.24%  
Thornburg Short Duration Municipal Fund Class I (0.05%) 1.05% 0.78% Dec. 30, 2013
Thornburg Short Duration Municipal Fund Class I | ICE BofAML 1-3 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.34% 1.62% 1.24%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation, and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Limited Term Municipal Fund
Limited Term Municipal Fund
Investment Goal

The primary investment goal of Limited Term Municipal Fund is to obtain as high a level of current income exempt from federal individual income tax as is consistent, in the view of the Fund’s investment advisor, with preservation of capital.

The secondary goal of the Fund is to reduce expected changes in its share price compared to longer intermediate and long-term bond portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Limited Term Municipal Fund
Thornburg Limited Term Municipal Fund - Class A
Thornburg Limited Term Municipal Fund - Class C
Thornburg Limited Term Municipal Fund - Class C2
Thornburg Limited Term Municipal Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.50% [2] 0.65% [2] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C and Class C2 shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Limited Term Municipal Fund
Thornburg Limited Term Municipal Fund - Class A
Thornburg Limited Term Municipal Fund - Class C
Thornburg Limited Term Municipal Fund - Class C2
Thornburg Limited Term Municipal Fund - Class I
Management Fees 0.27% 0.27% 0.27% 0.27%
Distribution and Service (12b-1) Fees 0.25% 0.50% 0.65% none
Other Expenses 0.17% 0.20% 0.80% 0.19%
Total Annual Fund Operating Expenses 0.69% 0.97% 1.72% 0.46%
Fee Waiver/Expense Reimbursement (0.48%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.69% 0.97% 1.24% 0.46%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class C2 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.24%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - Retail - Thornburg Limited Term Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Limited Term Municipal Fund - Class A 294 441 601 1,064
Thornburg Limited Term Municipal Fund - Class C 149 309 536 1,190
Thornburg Limited Term Municipal Fund - Class C2 191 495 888 1,990
Thornburg Limited Term Municipal Fund - Class I 47 148 258 579

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption - Retail - Thornburg Limited Term Municipal Fund - USD ($)
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Thornburg Limited Term Municipal Fund - Class C 99 309 536 1,190
Thornburg Limited Term Municipal Fund - Class C2 126 495 888 1,990
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.29% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by states and state agencies, local governments and their agencies and by United States territories and possessions. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity normally less than five years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than five years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 5 would be expected to change in price by approximately 5% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

The Fund normally invests 100% of its assets in municipal obligations, the income from which is exempt from the regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term Municipal Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C, Class C2 and Class I share performance to the ICE BofAML 1-10 Year U.S. Municipal Securities Index, a broad measure of market

performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results 

2.83%

6/30/2011

Lowest Quarterly Results

(2.43)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Limited Term Municipal Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Limited Term Municipal Fund - Class A (2.45%) 1.63% 1.48%    
Thornburg Limited Term Municipal Fund - Class A | After Taxes on Distributions (2.45%) 1.63% 1.48%    
Thornburg Limited Term Municipal Fund - Class A | After Taxes on Distributions and Sales (0.95%) 1.62% 1.52%    
Thornburg Limited Term Municipal Fund - Class A | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    
Thornburg Limited Term Municipal Fund - Class C (0.89%) 1.68% 1.38%    
Thornburg Limited Term Municipal Fund - Class C | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    
Thornburg Limited Term Municipal Fund - Class C2 (1.39%)     (0.22%) Oct. 01, 2020
Thornburg Limited Term Municipal Fund - Class C2 | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48%     1.09%  
Thornburg Limited Term Municipal Fund - Class I 0.04% 2.20% 1.92%    
Thornburg Limited Term Municipal Fund - Class I | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg California Limited Term Municipal Fund
Limited Term California Fund
Investment Goal

The primary investment goal of Limited Term California Fund is to obtain as high a level of current income exempt from federal and California state individual income taxes as is consistent, in the view of the Fund’s investment advisor, with preservation of capital.

The secondary goal of the Fund is to reduce expected changes in its share price compared to longer intermediate and long-term bond portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg California Limited Term Municipal Fund
Thornburg California Limited Term Municipal Fund - Class A
Thornburg California Limited Term Municipal Fund - Class C
Thornburg California Limited Term Municipal Fund - Class C2
Thornburg California Limited Term Municipal Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.25% none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.50% [2] 0.65% [2] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C and Class C2 shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg California Limited Term Municipal Fund
Thornburg California Limited Term Municipal Fund - Class A
Thornburg California Limited Term Municipal Fund - Class C
Thornburg California Limited Term Municipal Fund - Class C2
Thornburg California Limited Term Municipal Fund - Class I
Management Fees 0.49% 0.49% 0.49% 0.49%
Distribution and Service (12b-1) Fees 0.25% 0.50% 0.65% none
Other Expenses 0.18% 0.28% 5.36% 0.21%
Total Annual Fund Operating Expenses 0.92% 1.27% 6.50% 0.70%
Fee Waiver/Expense Reimbursement [1] (0.18%) (0.25%) (5.48%) (0.21%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.74% 1.02% 1.02% 0.49%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A, Class C, Class C2, and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.74%, 1.02%, 1.02%, and 0.49%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - Retail - Thornburg California Limited Term Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg California Limited Term Municipal Fund - Class A 299 494 706 1,315
Thornburg California Limited Term Municipal Fund - Class C 154 378 673 1,512
Thornburg California Limited Term Municipal Fund - Class C2 169 1,436 2,727 5,791
Thornburg California Limited Term Municipal Fund - Class I 50 203 369 851

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption - Retail - Thornburg California Limited Term Municipal Fund - USD ($)
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Thornburg California Limited Term Municipal Fund - Class C 104 378 673 1,512
Thornburg California Limited Term Municipal Fund - Class C2 104 1,436 2,727 5,791
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 16.22% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by the State of California and its agencies, and by California local governments and their agencies. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by United States territories and possessions. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity normally less than five years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than five years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 5 would be expected to change in price by approximately 5% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in California which are exempt from California and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in California or issued by United States territories and possessions and exempt from regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal or California income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal and California income taxes.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Single State Risk – Because the Fund invests primarily in obligations originating in California, the Fund’s share value may be more sensitive to adverse economic, political or regulatory developments in that state. Budgetary concerns, decreased revenues, and adverse conditions significant to a sector of the state, municipalities within the state, or local economies may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term California Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C, Class C2 and Class I share performance to the ICE BofAML 1-10 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

3.12%

6/30/2011

Lowest Quarterly Results

(2.70)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg California Limited Term Municipal Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg California Limited Term Municipal Fund - Class A (2.66%) 1.14% 1.38%    
Thornburg California Limited Term Municipal Fund - Class A | After Taxes on Distributions (2.66%) 1.14% 1.38%    
Thornburg California Limited Term Municipal Fund - Class A | After Taxes on Distributions and Sales (1.13%) 1.19% 1.41%    
Thornburg California Limited Term Municipal Fund - Class A | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    
Thornburg California Limited Term Municipal Fund - Class C (1.18%) 1.17% 1.27%    
Thornburg California Limited Term Municipal Fund - Class C | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    
Thornburg California Limited Term Municipal Fund - Class C2 (1.33%)     (0.28%) Oct. 01, 2020
Thornburg California Limited Term Municipal Fund - Class C2 | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48%     1.09%  
Thornburg California Limited Term Municipal Fund - Class I (0.23%) 1.71% 1.83%    
Thornburg California Limited Term Municipal Fund - Class I | ICE BofAML 1-10 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.48% 2.80% 2.28%    

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg New Mexico Intermediate Municipal Fund
Intermediate New Mexico Fund
Investment Goal

The primary investment goal of Intermediate New Mexico Fund is to obtain as high a level of current income exempt from federal and New Mexico state individual income taxes as is consistent, in the view of the Fund’s investment advisor, with preservation of capital.

The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg New Mexico Intermediate Municipal Fund
Thornburg New Mexico Intermediate Municipal Fund - Class A
Thornburg New Mexico Intermediate Municipal Fund - Class D
Thornburg New Mexico Intermediate Municipal Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.00% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] none none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg New Mexico Intermediate Municipal Fund
Thornburg New Mexico Intermediate Municipal Fund - Class A
Thornburg New Mexico Intermediate Municipal Fund - Class D
Thornburg New Mexico Intermediate Municipal Fund - Class I
Management Fees 0.50% 0.50% 0.50%
Distribution and Service (12b-1) Fees 0.25% 0.50% none
Other Expenses 0.23% 0.29% 0.21%
Total Annual Fund Operating Expenses 0.98% 1.29% 0.71%
Fee Waiver/Expense Reimbursement (0.05%) [1] (0.04%) [1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.98% 1.24% 0.67%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class D and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.24% and 0.67%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year) your costs would be:

Expense Example - Retail - Thornburg New Mexico Intermediate Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg New Mexico Intermediate Municipal Fund - Class A 298 506 731 1,377
Thornburg New Mexico Intermediate Municipal Fund - Class D 126 404 703 1,552
Thornburg New Mexico Intermediate Municipal Fund - Class I 68 223 391 879
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 7.43% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by the State of New Mexico and its agencies, and by New Mexico local governments and their agencies. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by United States territories and possessions. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than ten years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 10 would be expected to change in price by approximately 10% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in New Mexico which are exempt from New Mexico and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in New Mexico or issued by United States territories or possessions and exempt from regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which produce income not exempt from federal or New Mexico income tax because of market conditions, pending investment of idle funds or to afford liquidity. The

Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of the Fund’s income would be subject to federal and New Mexico income taxes.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Single State Risk Because the Fund invests primarily in obligations originating in New Mexico, the Fund’s share value may be more sensitive to adverse economic, political or regulatory developments in that state. Budgetary concerns, decreased revenues, and adverse conditions significant to a sector of the state, municipalities within the state, or local economies may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.

Non-diversification Risk The Fund is a non-diversified investment company, which means that it may invest a greater proportion of its assets in the securities of a single issuer. This may be riskier, because a default or other adverse condition affecting such an issuer could cause the Fund’s share price to decline to a greater degree.

Cybersecurity and Operational Risk Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Intermediate New Mexico Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class D and Class I share performance to the ICE BofAML 3-15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

2.83%

6/30/2011

Lowest Quarterly Results

(2.52)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg New Mexico Intermediate Municipal Fund
1 Year
5 Years
10 Years
Thornburg New Mexico Intermediate Municipal Fund - Class A (1.93%) 1.87% 1.82%
Thornburg New Mexico Intermediate Municipal Fund - Class A | After Taxes on Distributions (1.93%) 1.87% 1.82%
Thornburg New Mexico Intermediate Municipal Fund - Class A | After Taxes on Distributions and Sales (0.57%) 1.91% 1.93%
Thornburg New Mexico Intermediate Municipal Fund - Class A | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%
Thornburg New Mexico Intermediate Municipal Fund - Class D (0.23%) 2.01% 1.77%
Thornburg New Mexico Intermediate Municipal Fund - Class D | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%
Thornburg New Mexico Intermediate Municipal Fund - Class I 0.34% 2.59% 2.35%
Thornburg New Mexico Intermediate Municipal Fund - Class I | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg New York Intermediate Municipal Fund
Intermediate New York Fund
Investment Goal

The primary investment goal of Intermediate New York Fund is to obtain as high a level of current income exempt from federal, New York State and New York City individual income taxes as is consistent, in the view of the Fund’s investment advisor, with preservation of capital.

The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg New York Intermediate Municipal Fund
Thornburg New York Intermediate Municipal Fund - Class A
Thornburg New York Intermediate Municipal Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.00% none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg New York Intermediate Municipal Fund
Thornburg New York Intermediate Municipal Fund - Class A
Thornburg New York Intermediate Municipal Fund - Class I
Management Fees 0.50% 0.50%
Distribution and Service (12b-1) Fees 0.25% none
Other Expenses 0.39% 0.43%
Total Annual Fund Operating Expenses 1.14% 0.93%
Fee Waiver/Expense Reimbursement [1] (0.15%) (0.26%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.99% 0.67%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.99% and 0.67%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg New York Intermediate Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg New York Intermediate Municipal Fund - Class A 299 540 801 1,545
Thornburg New York Intermediate Municipal Fund - Class I 68 270 489 1,119
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 11.29% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by New York State and its agencies, and by New York State local governments and their agencies. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by United States territories and possessions. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than ten years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 10 would be expected to change in price by approximately 10% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in New York State which are exempt from New York State and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in New York or issued by United States territories and possessions and exempt from regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from

federal or New York income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of the Fund’s income would be subject to federal and New York State and City income taxes.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Single State Risk – Because the Fund invests primarily in obligations originating in New York, the Fund’s share value may be more sensitive to adverse economic, political or regulatory developments in that state. Budgetary concerns, decreased revenues, and adverse conditions significant to a sector of the state, municipalities within the state, or local economies may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.

Non-diversification Risk The Fund is a non-diversified investment company, which means that it may invest a greater proportion of its assets in the securities of a single issuer. This may be riskier, because a default or other adverse condition affecting such an issuer could cause the Fund’s share price to decline to a greater degree.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Intermediate New York Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A and Class I share performance

to the ICE BofAML 3-15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

3.86%

6/30/2011

Lowest Quarterly Results

(3.09)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg New York Intermediate Municipal Fund
1 Year
5 Years
10 Years
Thornburg New York Intermediate Municipal Fund - Class A (1.71%) 1.72% 1.88%
Thornburg New York Intermediate Municipal Fund - Class A | After Taxes on Distributions (1.72%) 1.72% 1.88%
Thornburg New York Intermediate Municipal Fund - Class A | After Taxes on Distributions and Sales (0.30%) 1.83% 1.97%
Thornburg New York Intermediate Municipal Fund - Class A | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%
Thornburg New York Intermediate Municipal Fund - Class I 0.64% 2.45% 2.42%
Thornburg New York Intermediate Municipal Fund - Class I | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Intermediate Municipal Fund
Intermediate Municipal Fund
Investment Goal

The primary investment goal of Intermediate Municipal Fund is to obtain as high a level of current income exempt from federal individual income tax as is consistent, in the view of the Fund’s investment advisor, with preservation of capital.

The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Intermediate Municipal Fund
Thornburg Intermediate Municipal Fund - Class A
Thornburg Intermediate Municipal Fund - Class C
Thornburg Intermediate Municipal Fund - Class C2
Thornburg Intermediate Municipal Fund - Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.00% none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.60% [2] 0.65% [2] none
[1] Up to a 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C and Class C2 shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Intermediate Municipal Fund
Thornburg Intermediate Municipal Fund - Class A
Thornburg Intermediate Municipal Fund - Class C
Thornburg Intermediate Municipal Fund - Class C2
Thornburg Intermediate Municipal Fund - Class I
Management Fees 0.47% 0.47% 0.47% 0.47%
Distribution and Service (12b-1) Fees 0.25% 0.60% 0.65% none
Other Expenses 0.19% 0.23% 1.50% 0.20%
Total Annual Fund Operating Expenses [1] 0.91% 1.30% 2.62% 0.67%
Fee Waiver/Expense Reimbursement (0.14%) (0.16%) (1.48%) (0.14%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.77% 1.14% 1.14% 0.53%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A, Class C, Class C2, and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.77%, 1.14%, 1.14%, and 0.53%. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example - Retail - Thornburg Intermediate Municipal Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Intermediate Municipal Fund - Class A 277 471 680 1,285
Thornburg Intermediate Municipal Fund - Class C 176 396 698 1,554
Thornburg Intermediate Municipal Fund - Class C2 181 673 1,258 2,844
Thornburg Intermediate Municipal Fund - Class I 54 200 359 821

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption - Retail - Thornburg Intermediate Municipal Fund - USD ($)
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Thornburg Intermediate Municipal Fund - Class C 116 396 698 1,554
Thornburg Intermediate Municipal Fund - Class C2 116 673 1,258 2,844
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 10.20% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by states and state agencies, local governments and their agencies, and by United States territories and possessions. Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated by a nationally recognized statistical rating organization at the time of purchase as investment grade or, if unrated, are issued by obligors which Thornburg determines have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund’s portfolio is “laddered” by investing in obligations of different maturities so that some obligations mature during each of the coming years.

Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than ten years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 10 would be expected to change in price by approximately 10% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to

changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

The Fund normally invests 100% of its assets in municipal obligations, the income from which is exempt from the regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Intermediate Municipal Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C, Class C2 and Class I share performance to the ICE BofAML 3-15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

3.41%

6/30/2011

Lowest Quarterly Results

(3.23)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Intermediate Municipal Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Intermediate Municipal Fund - Class A (1.06%) 2.49% 2.51%    
Thornburg Intermediate Municipal Fund - Class A | After Taxes on Distributions (1.06%) 2.49% 2.51%    
Thornburg Intermediate Municipal Fund - Class A | After Taxes on Distributions and Sales 0.27% 2.46% 2.47%    
Thornburg Intermediate Municipal Fund - Class A | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%    
Thornburg Intermediate Municipal Fund - Class C 0.02% 2.54% 2.37%    
Thornburg Intermediate Municipal Fund - Class C | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%    
Thornburg Intermediate Municipal Fund - Class C2 (0.03%)     1.53% Oct. 01, 2020
Thornburg Intermediate Municipal Fund - Class C2 | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94%     2.01%  
Thornburg Intermediate Municipal Fund - Class I 1.23% 3.15% 3.00%    
Thornburg Intermediate Municipal Fund - Class I | ICE BofAML 3-15 Year U.S. Municipal Securities Index (reflects no deduction for fees, expenses, or taxes) 0.94% 3.77% 3.22%    

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retail | Thornburg Strategic Municipal Income Fund
Strategic Municipal Income Fund
Investment Goal

The Fund seeks a high level of current income exempt from federal individual income tax.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about this and other discounts and sales charge waivers is available from your financial intermediary, in the Prospectus under the captions “Class A Sales Charge Waivers,” beginning on page 146, and “Appendix A – Sales Charge Waivers Offered by Financial Intermediaries,” beginning on page 200, and in the Statement of Additional Information under the caption “Additional Information Respecting Purchase and Redemption of Shares,” beginning on page 108.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retail - Thornburg Strategic Municipal Income Fund
Thornburg Strategic Municipal Income Fund Class A
Thornburg Strategic Municipal Income Fund Class C
Thornburg Strategic Municipal Income Fund Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) 2.00% none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none [1] 0.60% [2] none
[1] A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.
[2] Imposed only on redemptions of Class C shares within 12 months of purchase.
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retail - Thornburg Strategic Municipal Income Fund
Thornburg Strategic Municipal Income Fund Class A
Thornburg Strategic Municipal Income Fund Class C
Thornburg Strategic Municipal Income Fund Class I
Management Fees 0.75% 0.75% 0.75%
Distribution and Service (12b-1) Fees 0.25% 0.60% none
Other Expenses 0.26% 0.36% 0.22%
Total Annual Fund Operating Expenses 1.26% 1.71% 0.97%
Fee Waiver/Expense Reimbursement [1] (0.45%) (0.43%) (0.38%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.81% 1.28% 0.59%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class A, Class C, and Class I expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.81%, 1.28%, and 0.59%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retail - Thornburg Strategic Municipal Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Strategic Municipal Income Fund Class A 281 548 835 1,653
Thornburg Strategic Municipal Income Fund Class C 190 497 888 1,984
Thornburg Strategic Municipal Income Fund Class I 60 271 499 1,155

You would pay the following expenses if you did not redeem your Class C shares:

Expense Example, No Redemption
Expense Example, No Redemption, 1 Year
Expense Example, No Redemption, 3 Years
Expense Example, No Redemption, 5 Years
Expense Example, No Redemption, 10 Years
Retail | Thornburg Strategic Municipal Income Fund | Thornburg Strategic Municipal Income Fund Class C | USD ($) 130 497 888 1,984
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 10.43% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s investments in pursuing the Fund’s investment goal. The Fund invests principally in a portfolio of municipal obligations issued by states and state agencies, local governments and their agencies, and by United States territories and possessions. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, the difference in yields between higher and lower-rated obligations, and analysis of specific obligations. The Fund invests in obligations and participations in obligations of any credit quality. The Fund may invest up to 50 percent of its portfolio in lower-quality debt obligations rated by a nationally recognized statistical rating organization at the time of purchase as below investment grade (sometimes called “junk” bonds or “high yield” bonds) or, if unrated, issued by obligors which Thornburg determines have comparable below investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding below investment grade obligations. The Fund may also invest in obligations that are in default at the time of purchase. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants.

The Fund may invest in municipal obligations of any maturity, but seeks to maintain a portfolio of investments having a dollar-weighted average effective duration of normally one to ten years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 10 would be expected to change in price by approximately 10% in response to a 1% change in interest rates. During temporary periods the Fund’s average effective duration and average portfolio maturity may be reduced for defensive purposes. There is no limitation on the duration or maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund attempts to reduce changes in its share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to

changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.  The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

The Fund normally invests 100% of its assets in municipal obligations, the income from which is exempt from the regular federal income tax. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund’s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax. Gains realized on investments held by the Fund and not offset by realized losses will be subject to federal income tax.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund’s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund’s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. For example, municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental agencies or issuers to discontinue payments to the Fund under the municipal leases.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund’s investments in lower-rated and unrated municipal obligations (including particularly “junk” or “high yield” bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations (including particularly “junk” or “high yield” bonds) may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears beginning on page 118 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Strategic Municipal Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the ICE BofAML US Municipal Master Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at Thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class A Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

4.69%

6/30/2011

Lowest Quarterly Results

(3.57)%

12/31/2016

The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retail - Thornburg Strategic Municipal Income Fund
1 Year
5 Years
10 Years
Thornburg Strategic Municipal Income Fund Class A (0.83%) 2.65% 3.12%
Thornburg Strategic Municipal Income Fund Class A | After Taxes on Distributions (0.83%) 2.65% 3.10%
Thornburg Strategic Municipal Income Fund Class A | After Taxes on Distributions and Sales 0.26% 2.59% 2.98%
Thornburg Strategic Municipal Income Fund Class A | ICE BofAML US Municipal Master Index (reflects no deduction for fees, expenses, or taxes) 1.83% 4.23% 3.88%
Thornburg Strategic Municipal Income Fund Class C 0.21% 2.57% 2.94%
Thornburg Strategic Municipal Income Fund Class C | ICE BofAML US Municipal Master Index (reflects no deduction for fees, expenses, or taxes) 1.83% 4.23% 3.88%
Thornburg Strategic Municipal Income Fund Class I 1.50% 3.29% 3.61%
Thornburg Strategic Municipal Income Fund Class I | ICE BofAML US Municipal Master Index (reflects no deduction for fees, expenses, or taxes) 1.83% 4.23% 3.88%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class A shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Global Opportunities Fund
Global Opportunities Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types from issuers around the world.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Global Opportunities Fund
Thornburg Global Opportunities Fund - Class R3
Thornburg Global Opportunities Fund - Class R4
Thornburg Global Opportunities Fund - Class R5
Thornburg Global Opportunities Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Global Opportunities Fund
Thornburg Global Opportunities Fund - Class R3
Thornburg Global Opportunities Fund - Class R4
Thornburg Global Opportunities Fund - Class R5
Thornburg Global Opportunities Fund - Class R6
Management Fees 0.85% 0.85% 0.85% 0.85%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses 0.72% 0.73% 0.51% 0.15%
Total Annual Fund Operating Expenses 2.07% 1.83% 1.36% 1.00%
Fee Waiver/Expense Reimbursement [1] (0.57%) (0.43%) (0.37%) (0.15%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.50% 1.40% 0.99% 0.85%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, Class R5, and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.50%, 1.40%, 0.99%, and 0.85%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Global Opportunities Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Global Opportunities Fund - Class R3 153 594 1,061 2,355
Thornburg Global Opportunities Fund - Class R4 143 534 950 2,113
Thornburg Global Opportunities Fund - Class R5 101 394 709 1,603
Thornburg Global Opportunities Fund - Class R6 87 303 538 1,211
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 25.48% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goal by investing primarily in a broad range of equity securities, including common stocks, preferred stocks and publicly traded real estate investment trusts. The Fund may invest in any stock or other equity security which its investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), believes may assist the Fund in pursuing its goal, including smaller companies with market capitalizations of less than $500 million.

The Fund portfolio includes investments in both domestic securities and securities of issuers domiciled in or economically tied to countries outside the United States, including developing countries. Relative proportions of each will vary from time to time, depending upon the advisor’s view of specific investment opportunities and macro-economic factors. Under normal market conditions, the Fund invests a significant portion of its assets in issuers domiciled in or economically tied to countries outside the United States.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for securities, and analysis of specific issuers.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Real Estate Risk – The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

 

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Global Opportunities Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares of the Fund vary in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the MSCI ACWI Net Total Return USD Index, which represents a broad measure of both domestic and foreign equity market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

21.70%

6/30/2020

Lowest Quarterly Results

(24.86)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Global Opportunities Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Global Opportunities Fund - Class R3 14.18% 11.33% 12.66%    
Thornburg Global Opportunities Fund - Class R3 | After Taxes on Distributions 10.57% 9.93% 11.85%    
Thornburg Global Opportunities Fund - Class R3 | After Taxes on Distributions and Sales 10.58% 8.71% 10.39%    
Thornburg Global Opportunities Fund - Class R3 | MSCI AC World Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%    
Thornburg Global Opportunities Fund - Class R4 14.28% 11.44% 12.76%    
Thornburg Global Opportunities Fund - Class R4 | MSCI AC World Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%    
Thornburg Global Opportunities Fund - Class R5 14.73% 11.89% 13.22%    
Thornburg Global Opportunities Fund - Class R5 | MSCI AC World Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54% 14.40% 11.85%    
Thornburg Global Opportunities Fund - Class R6 14.91%     11.00% Apr. 10, 2017
Thornburg Global Opportunities Fund - Class R6 | MSCI AC World Index (reflects no deduction for fees, expenses, or U.S. taxes) 18.54%     13.74%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg International Equity Fund
International Equity Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types. The goal of the Fund is to seek some current income.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg International Equity Fund
Thornburg International Equity Fund - Class R3
Thornburg International Equity Fund - Class R4
Thornburg International Equity Fund - Class R5
Thornburg International Equity Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg International Equity Fund
Thornburg International Equity Fund - Class R3
Thornburg International Equity Fund - Class R4
Thornburg International Equity Fund - Class R5
Thornburg International Equity Fund - Class R6
Management Fees 0.74% 0.74% 0.74% 0.74%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses [1] 0.37% 0.41% 0.42% 0.14%
Total Annual Fund Operating Expenses 1.61% 1.40% 1.16% 0.88%
Fee Waiver/Expense Reimbursement [2] (0.25%) (0.24%) (0.26%) (0.18%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.36% 1.16% 0.90% 0.70%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes R3, R4, R5, and R6 would have been 0.67%, 0.71%, 0.72% and 0.44%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, and Class R5 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.36%, 1.16%, 0.90%, and 0.70%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg International Equity Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg International Equity Fund - Class R3 138 484 853 1,890
Thornburg International Equity Fund - Class R4 118 420 743 1,659
Thornburg International Equity Fund - Class R5 92 343 613 1,386
Thornburg International Equity Fund - Class R6 72 263 470 1,068
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 42.85% of the average value of its portfolio.

Principal Investment Strategies

The Fund invests primarily in common stocks of non-U.S. companies and depositary receipts associated with such stocks. The Fund may invest in developing countries, but under normal conditions those investments are expected to comprise a smaller proportion of the Fund than investments in developed countries. Under normal conditions, the Fund will invest at least 80% of its net assets in common stocks or depositary receipts.

The Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), intends to invest on an opportunistic basis where the Fund’s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks the Fund categorizes as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies.

Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund’s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

profitability

price/earnings ratio

price/book value ratio

price/cash flow ratio

debt/capital ratio

dividend characteristics

security and consistency of revenues

EV (enterprise value)/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio

undervalued assets

earnings growth potential

industry growth characteristics

industry leadership

franchise value

potential for favorable developments

EBIT (earnings before interest and taxes)/interest expense ratio

The Fund categorizes its equity investments in the following three categories:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth, profitability, cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its net assets in common stocks or depositary receipts may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Risks Affecting Investments in China – A significant portion of the Fund’s assets may be invested in companies exposed to China. Risks affecting investments in China include a potential downturn in the Chinese economy, reduced liquidity or increased price volatility in the Chinese securities markets as a result of trading suspensions affecting Chinese issuers or other factors, the potential that the Chinese government may expand restrictions on foreign investments or the repatriation of capital, and the implementation of new tariffs or other trade barriers by China or its trading partners. A lack of transparency respecting Chinese companies may also reduce the Fund’s ability to conduct diligence respecting those companies’ accounting and governance standards, which may in turn reduce the Fund’s ability to detect fraudulent practices that may adversely affect the companies’ stock prices.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares vary in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the MSCI ACWI ex USA Net Total Return USD Index (primary index) and the MSCI EAFE Net Total Return USD Index (secondary index), each of which is a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Effective as of February 1, 2022, the MSCI ACWI ex USA Net Total Return USD Index replaced the MSCI EAFE Net Total Return USD Index as the Fund’s primary index. Thornburg believes that the MSCI ACWI ex USA Net Total Return USD Index more closely aligns with the Fund’s investment strategies than the MSCI EAFE Net Total Return USD Index.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

18.40%

6/30/2020

Lowest Quarterly Results

(20.95)%

9/30/2011

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg International Equity Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg International Equity Fund - Class R3 7.10% 10.83% 7.93%    
Thornburg International Equity Fund - Class R3 | After Taxes on Distributions 2.98% 8.40% 5.94%    
Thornburg International Equity Fund - Class R3 | After Taxes on Distributions and Sales 5.55% 7.90% 5.80%    
Thornburg International Equity Fund - Class R3 | MSCI AC World ex-U.S. Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%    
Thornburg International Equity Fund - Class R3 | MSCI EAFE Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%    
Thornburg International Equity Fund - Class R4 7.30% 11.05% 8.14%    
Thornburg International Equity Fund - Class R4 | MSCI AC World ex-U.S. Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%    
Thornburg International Equity Fund - Class R4 | MSCI EAFE Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%    
Thornburg International Equity Fund - Class R5 7.57% 11.34% 8.43%    
Thornburg International Equity Fund - Class R5 | MSCI AC World ex-U.S. Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61% 7.28%    
Thornburg International Equity Fund - Class R5 | MSCI EAFE Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55% 8.03%    
Thornburg International Equity Fund - Class R6 7.77% 11.56%   7.82% May 01, 2012
Thornburg International Equity Fund - Class R6 | MSCI AC World ex-U.S. Index (reflects no deduction for fees, expenses, or U.S. taxes) 7.82% 9.61%   6.55%  
Thornburg International Equity Fund - Class R6 | MSCI EAFE Index (reflects no deduction for fees, expenses, or U.S. taxes) 11.26% 9.55%   7.41%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg International Growth Fund
International Growth Fund
Investment Goal

The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg International Growth Fund
Thornburg International Growth Fund - Class R3
Thornburg International Growth Fund - Class R4
Thornburg International Growth Fund - Class R5
Thornburg International Growth Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg International Growth Fund
Thornburg International Growth Fund - Class R3
Thornburg International Growth Fund - Class R4
Thornburg International Growth Fund - Class R5
Thornburg International Growth Fund - Class R6
Management Fees 0.80% 0.80% 0.80% 0.80%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses [1] 0.58% 0.57% 0.46% 0.15%
Total Annual Fund Operating Expenses 1.88% 1.62% 1.26% 0.95%
Fee Waiver/Expense Reimbursement [2] (0.38%) (0.22%) (0.27%) (0.06%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.50% 1.40% 0.99% 0.89%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes R3, R4, R5, and R6 would have been 0.59 %, 0.58%, 0.47% and 0.16%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, Class R5 and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.50%, 1.40%, 0.99%, and 0.89%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg International Growth Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg International Growth Fund - Class R3 153 554 981 2,170
Thornburg International Growth Fund - Class R4 143 490 861 1,903
Thornburg International Growth Fund - Class R5 101 373 666 1,499
Thornburg International Growth Fund - Class R6 91 297 520 1,161
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 34.41% of the average value of its portfolio.

Principal Investment Strategies

The Fund expects to invest primarily in equity securities from issuers around the world (primarily common stocks) selected for their growth potential and, under normal market conditions, invests at least 75% of its assets in foreign securities or depositary receipts of foreign securities. However, the Fund may own a variety of securities, including domestic equity securities. The Fund may invest in developing countries.

The Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”) intends to invest in companies that it believes will have growing revenues and earnings. The Fund can invest in companies of any size, from larger, well-established companies to smaller, emerging growth companies.

Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

business model

industry growth potential

industry leadership

asset appreciation potential

potential size of business

price/earnings ratio

price/revenue ratio

PE/growth rate ratio

price/cash flow ratio

enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio

management strength

debt/capital ratio

The Fund typically makes equity investments in the following three types of companies:

Growth Industry Leaders: Companies in this category often have leadership positions in growing markets. In some cases these companies may have dominant market share. These companies tend to be larger and more established.

Consistent Growers: Companies in this category generally exhibit steady earnings or revenue growth, or both. These companies may have subscription or other recurring revenue profiles. Given their business models, these companies may outperform in weak markets.

Emerging Growth Companies: Companies often addressing a new market or carving out a niche in an existing market. Companies in this category may experience rapid growth, and tend to be smaller, earlier stage companies. These companies may exhibit high volatility.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

In conjunction with individual issuer analysis, Thornburg may identify and invest at times with a greater emphasis in industries or economic sectors it expects to experience growth. This approach may at times produce a greater emphasis on investment in certain industries or economic sectors, such as technology, financial services, healthcare or biotechnology. The Fund does not have a strategy to invest in particular industry or economic sectors, and its exposures to particular industries or economic sectors are expected to vary over time. Investment decisions are also based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for securities.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies, including smaller, earlier stage companies, may involve additional risks. These risks may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in International Growth Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares vary in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the MSCI ACWI ex USA Growth Net Total Return USD Index, a market capitalization weighted index which includes growth companies in developed and emerging markets throughout the world, excluding the United States. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

25.89%

6/30/2020

Lowest Quarterly Results

(17.77)%

12/31/2018

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg International Growth Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg International Growth Fund - Class R3 (4.69%) 12.21% 10.04%    
Thornburg International Growth Fund - Class R3 | After Taxes on Distributions (6.19%) 11.34% 9.34%    
Thornburg International Growth Fund - Class R3 | After Taxes on Distributions and Sales (1.67%) 9.63% 8.10%    
Thornburg International Growth Fund - Class R3 | MSCI AC World ex-U.S. Growth Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%    
Thornburg International Growth Fund - Class R4 (4.56%) 12.35% 10.15%    
Thornburg International Growth Fund - Class R4 | MSCI AC World ex-U.S. Growth Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%    
Thornburg International Growth Fund - Class R5 (4.22%) 12.79% 10.59%    
Thornburg International Growth Fund - Class R5 | MSCI AC World ex-U.S. Growth Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06% 9.13%    
Thornburg International Growth Fund - Class R6 (4.08%) 12.91%   8.93% Feb. 01, 2013
Thornburg International Growth Fund - Class R6 | MSCI AC World ex-U.S. Growth Index (reflects no deduction for fees, expenses, or U.S. taxes) 5.09% 13.06%   7.89%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Developing World Fund
Developing World Fund
Investment Goal

The Fund’s primary investment goal is long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Developing World Fund
Thornburg Developing World Fund Class R5
Thornburg Developing World Fund Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Developing World Fund
Thornburg Developing World Fund Class R5
Thornburg Developing World Fund Class R6
Management Fees 0.94% 0.94%
Distribution and Service (12b-1) Fees none none
Other Expenses 0.76% 0.17%
Total Annual Fund Operating Expenses 1.70% 1.11%
Fee Waiver/Expense Reimbursement [1] (0.66%) (0.17%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.04% 0.94%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R5 and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.04% and 0.94%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Developing World Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Developing World Fund Class R5 106 471 861 1,954
Thornburg Developing World Fund Class R6 96 336 595 1,336
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 61.50% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions the Fund invests at least 80% of its assets in equity securities of developing country issuers. A developing country issuer is a company or sovereign entity that is domiciled or otherwise tied economically to one or more developing countries. The Fund may invest in issuers of any size of capitalization, including small companies.

Currently, the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”) considers developing countries to include most Central and South American, African, Asian and Eastern European nations, including, but not limited to, Argentina, Austria, Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hong Kong, Hungary, India, Indonesia, Israel, South Korea, Malaysia, Mexico, Morocco, Nigeria, Pakistan, Peru, Philippines, Poland, Qatar, Romania, the Russian Federation, Slovenia, South Africa, Taiwan, Thailand, Turkey, Ukraine, the United Arab Emirates and Vietnam. Thornburg identifies what it considers to be developing countries based upon its own analysis of measures of industrialization, economic growth, population growth and other factors, and may also consider classifications by the World Bank, the International Finance Corporation, the United Nations and independent financial services firms that maintain indices of developing countries.

Thornburg considers a variety of factors to determine whether an investment is tied economically to one or more developing countries, including (i) whether or not a significant portion of the issuer’s revenues or assets are derived from or are located in developing countries, (ii) the primary trading market of the issuer’s securities, (iii) the locations of its principal offices or operations, (iv) the source of any governmental guarantees or other supports, (v) identification of the issuer’s securities within an index or other listing indicating its location in a particular developing country or region, and (vi) the extent to which the investment is otherwise exposed to the economic fortunes and risks of developing countries.

The Fund expects that under normal conditions its assets will be invested in issuers domiciled in or tied economically to a variety of different countries.

The Fund’s policy of investing at least 80% of its assets in developing country issuers may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Among the specific factors considered in identifying securities for inclusion in the Fund are domestic and international economic developments, outlooks for securities markets, the supply and demand for equity securities, and analysis of specific issuers. The Fund typically makes its equity investments in the following three types of issuers:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth, profitability, cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility. These risks may be more pronounced for the Fund’s investments in developing countries.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of an equity security may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protections.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Risks Affecting Investments in China – A significant portion of the Fund’s assets may be invested in companies exposed to China. Risks affecting investments in China include a potential downturn in the Chinese economy, reduced liquidity or increased price volatility in the Chinese securities markets as a result of trading suspensions affecting Chinese issuers or other factors, the potential that the Chinese government may expand restrictions on foreign investments or the repatriation of capital, and the implementation of new tariffs or other trade barriers by China or its trading partners. A lack of transparency respecting Chinese companies may also reduce the Fund’s ability to conduct diligence respecting those companies’ accounting and governance standards, which may in turn reduce the Fund’s ability to detect fraudulent practices that may adversely affect the companies’ stock prices.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund’s investments in developing countries.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Developing World Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R5 shares have been different in each full year shown. The average annual total return figures compare Class R5 and Class R6 share performance to the MSCI Emerging Markets Net Total Return USD Index, which represents a broad measure of equity market performance of emerging markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R5 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

21.77%

6/30/2020

Lowest Quarterly Results

(24.75)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Developing World Fund
1 Year
5 Years
Since Inception
Inception Date
Thornburg Developing World Fund Class R5 (2.65%) 12.41% 5.91% Feb. 01, 2013
Thornburg Developing World Fund Class R5 | After Taxes on Distributions (2.65%) 12.07% 5.63%  
Thornburg Developing World Fund Class R5 | After Taxes on Distributions and Sales (1.57%) 9.74% 4.56%  
Thornburg Developing World Fund Class R5 | MSCI Emerging Markets Index (reflects no deduction for fees, expenses, or U.S. taxes) (2.54%) 9.87% 4.00%  
Thornburg Developing World Fund Class R6 (2.56%) 12.52% 6.01% Feb. 01, 2013
Thornburg Developing World Fund Class R6 | MSCI Emerging Markets Index (reflects no deduction for fees, expenses, or U.S. taxes) (2.54%) 9.87% 4.00%  

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R5 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Small/Mid Cap Core Fund
Small/Mid Cap Core Fund
Investment Goal

The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.

The secondary, non-fundamental goal of the Fund is to seek some current income.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Small/Mid Cap Core Fund
Thornburg Small/Mid Cap Core Fund - Class R3
Thornburg Small/Mid Cap Core Fund - Class R4
Thornburg Small/Mid Cap Core Fund - Class R5
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Small/Mid Cap Core Fund
Thornburg Small/Mid Cap Core Fund - Class R3
Thornburg Small/Mid Cap Core Fund - Class R4
Thornburg Small/Mid Cap Core Fund - Class R5
Management Fees 0.85% 0.85% 0.85%
Distribution and Service (12b-1) Fees 0.50% 0.25% none
Other Expenses [1] 0.44% 0.66% 0.61%
Total Annual Fund Operating Expenses 1.79% 1.76% 1.46%
Fee Waiver/Expense Reimbursement [2] (0.48%) (0.55%) (0.51%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.31% 1.21% 0.95%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes R3, R4, and R5 would have been 0.46%, 0.68% and 0.63%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4 and Class R5 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.31%, 1.21%, and 0.95%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Small/Mid Cap Core Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Small/Mid Cap Core Fund - Class R3 133 517 925 2,066
Thornburg Small/Mid Cap Core Fund - Class R4 123 501 903 2,028
Thornburg Small/Mid Cap Core Fund - Class R5 97 412 749 1,703
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 135.80% of the average value of its portfolio.

Principal Investment Strategies

Under normal conditions, the Fund invests at least 80% of its net assets in small- and mid-capitalization companies. The Fund currently defines small- and mid-capitalization companies to be those within the market capitalization range comprised by the Russell 2500 Index – Total Return. As of November 30, 2021, the market capitalization range of the Russell 2500 Index – Total Return was approximately $14 million to $33 billion. The market capitalization range of the Russell 2500 Index – Total Return changes over time and, as a result, the capitalization range of companies in which the Fund invests will also change. The Fund may change the definition of what constitutes “small- and mid-capitalization companies” without advance notice to shareholders.

The Fund expects to invest primarily in domestic common stocks. However, the Fund may own foreign common stocks which, in the opinion of the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), offer prospects for meeting the Fund’s investment goals.

With its core approach to stock selection, the Fund seeks to invest in a broadly diversified portfolio of companies the Fund categorizes as basic values, consistent earners, and emerging franchises, as described in more detail below. The relative proportions of securities invested in each of those categories will vary over time.

Thornburg primarily takes a bottom-up, fundamental view in determining the attractiveness of individual securities and in making investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

durable business model

industry growth potential

innovation driving the potential to disrupt entrenched competitors

intrinsic value appreciation potential

potential size of addressable market

management strength

leverage

return on invested capital

valuation metrics, including: price/earnings (“PE”) ratio; enterprise value/revenue ratio; PE/growth rate ratio, enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio; and free cash flow yield.

The Fund categorizes its investments in the following three categories:

Basic Value: Companies generally operating in mature or cyclical industries and which generally exhibit more economic sensitivity and/or higher volatility in earnings and cash flow.

Consistent Earner: Companies which generally exhibit predictable growth and profitability, and consistent cash flow and/or dividends.

Emerging Franchise: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its assets in small- and mid-capitalization companies may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of an equity security may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, earlier stages of development and lack of well-established businesses, more limited access to markets and financial resources, greater vulnerability to competition and market risks and fluctuations, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments. Relative to the stocks of large capitalization companies, the stocks of small- and mid-capitalization companies may be thinly traded and sales may result in higher transaction costs. Also, small- and mid-capitalization companies may perform poorly during times of economic stress.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in the Small/Mid Cap Core Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3, Class R4 and Class R5 share performance to Russell 2500 Index—Total Return, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

18.90%

6/30/2020

Lowest Quarterly Results

(26.31)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Small/Mid Cap Core Fund
1 Year
5 Years
10 Years
Thornburg Small/Mid Cap Core Fund - Class R3 13.78% 12.77% 13.23%
Thornburg Small/Mid Cap Core Fund - Class R3 | After Taxes on Distributions 5.06% 10.88% 12.23%
Thornburg Small/Mid Cap Core Fund - Class R3 | After Taxes on Distributions and Sales 11.89% 9.85% 10.91%
Thornburg Small/Mid Cap Core Fund - Class R3 | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%
Thornburg Small/Mid Cap Core Fund - Class R4 13.90% 12.88% 13.35%
Thornburg Small/Mid Cap Core Fund - Class R4 | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%
Thornburg Small/Mid Cap Core Fund - Class R5 14.19% 13.18% 13.64%
Thornburg Small/Mid Cap Core Fund - Class R5 | Russell 2500 Index-Total Return (reflects no deduction for fees, expenses, or taxes) 18.18% 13.75% 14.15%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

The performance information shown above may include gains attributable to the Fund’s investments in shares of companies through initial public offerings (“IPOs”). There can be no assurance that the Fund will have continued access to profitable IPOs and, as the Fund’s assets grow, the impact of the Fund’s investment in IPOs on the performance of the Fund may decline.

Retirement | Thornburg Small/Mid Cap Growth Fund
Small/Mid Cap Growth Fund
Investment Goal

The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Small/Mid Cap Growth Fund
Thornburg Small/Mid Cap Growth Fund - Class R3
Thornburg Small/Mid Cap Growth Fund - Class R4
Thornburg Small/Mid Cap Growth Fund - Class R5
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Small/Mid Cap Growth Fund
Thornburg Small/Mid Cap Growth Fund - Class R3
Thornburg Small/Mid Cap Growth Fund - Class R4
Thornburg Small/Mid Cap Growth Fund - Class R5
Management Fees 0.86% 0.86% 0.86%
Distribution and Service (12b-1) Fees 0.50% 0.25% none
Other Expenses 0.43% 1.06% 0.45%
Total Annual Fund Operating Expenses 1.79% 2.17% 1.31%
Fee Waiver/Expense Reimbursement [1] (0.33%) (0.81%) (0.36%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.46% 1.36% 0.95%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4 and Class R5 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.46%, 1.36%, and 0.95%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Small/Mid Cap Growth Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Small/Mid Cap Growth Fund - Class R3 149 531 939 2,078
Thornburg Small/Mid Cap Growth Fund - Class R4 138 601 1,090 2,440
Thornburg Small/Mid Cap Growth Fund - Class R5 97 380 684 1,548
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 161.43% of the average value of its portfolio.

Principal Investment Strategies

Under normal conditions, the Fund invests at least 80% of its net assets in small- and mid-capitalization companies. The Fund currently defines small- and mid-capitalization companies to be those within the market capitalization range comprised by the Russell 2500 Growth Index – Total Return. As of November 30, 2021, the market capitalization range of the Russell 2500 Growth Index – Total Return was approximately $5 million to $33 billion. The market capitalization range of the Russell 2500 Growth Index – Total Return changes over time and, as a result, the capitalization range of companies in which the Fund invests will also change. The Fund may change the definition of what constitutes “small- and mid-capitalization companies” without advance notice to shareholders.

The Fund expects to invest primarily in domestic common stocks. However, the Fund may own foreign common stocks which, in the opinion of the Fund’s investment advisor, Thornburg Investment Management, Inc. (“Thornburg”), offer prospects for meeting the Fund’s investment goal.

The Fund seeks to invest in a diversified portfolio of companies the Fund categorizes as consistent growers, disruptors, and emerging franchises, as described in more detail below. The relative proportions of securities invested in each of those categories will vary over time.

Thornburg primarily takes a bottom-up, fundamental view in determining the attractiveness of individual securities and in making investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:

earnings growth potential

durable business model

industry growth potential

innovation driving the potential to disrupt entrenched competitors

intrinsic value appreciation potential

potential size of addressable market

management strength

leverage

return on invested capital

valuation metrics, including: price/earnings (“PE”) ratio; enterprise value/revenue ratio; PE/growth rate ratio, enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio; and free cash flow yield.

The Fund categorizes its equity investments in the following three categories:

Consistent Growers: Companies in this category generally exhibit steady earnings or revenue growth, or both. These companies may have subscription or other recurring revenue profiles. Given their business models, these companies may outperform in weak markets.

Disruptors: Companies which are at the early stages of growth; which usually possess highly innovative or differentiated products and services, but which may require substantial additional time or investment to capitalize on market opportunities and achieve profitability. Companies in this category often are in leadership positions in growing markets. These companies may operate in niche markets with large or dominant share.

Emerging Franchises: Companies with the potential to grow at an above average rate because of a product or service that is establishing a new market and/or taking share from existing participants.

Inclusion of any investment in any of the three described categories represents the opinion of the advisor concerning the characteristics and prospects of the investment. There is no assurance that any company selected for investment will, once categorized in one of the three described investment categories, continue to have the positive characteristics or fulfill the expectations that the advisor had for the company when it was selected for investment, and any such company may not grow or may decline in earnings and size.

The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

The Fund’s policy of investing at least 80% of its assets in small- and mid-capitalization companies may be changed by the Fund’s Trustees without a shareholder vote upon 60 days’ notice to shareholders.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of a security may decline in response to developments affecting the specific issuer of the security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, earlier stages of development and lack of well-established businesses, more limited access to markets

and financial resources, greater vulnerability to competition and market risks and fluctuations, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments. Relative to the stocks of large capitalization companies, the stocks of small- and mid-capitalization companies may be thinly traded and sales may result in higher transaction costs. Also, small- and mid-capitalization companies may perform poorly during times of economic stress.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in the Small/Mid Cap Growth Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares vary in each full year shown. The average annual total return figures compare Class R3, Class R4 and Class R5 share performance to the Russell 2500 Growth Index—Total Return, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

30.91%

6/30/2020

Lowest Quarterly Results

(18.72)%

9/30/2011

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Small/Mid Cap Growth Fund
1 Year
5 Years
10 Years
Thornburg Small/Mid Cap Growth Fund - Class R3 (4.47%) 15.92% 13.74%
Thornburg Small/Mid Cap Growth Fund - Class R3 | After Taxes on Distributions (12.29%) 13.08% 12.34%
Thornburg Small/Mid Cap Growth Fund - Class R3 | After Taxes on Distributions and Sales 3.54% 12.80% 11.57%
Thornburg Small/Mid Cap Growth Fund - Class R3 | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%
Thornburg Small/Mid Cap Growth Fund - Class R4 (4.38%) 16.04% 13.86%
Thornburg Small/Mid Cap Growth Fund - Class R4 | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%
Thornburg Small/Mid Cap Growth Fund - Class R5 (4.00%) 16.51% 14.32%
Thornburg Small/Mid Cap Growth Fund - Class R5 | Russell 2500 Growth Index-Total Return (reflects no deduction for fees, expenses, or taxes) 5.04% 17.65% 15.75%

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Investment Income Builder Fund
Income Builder Fund
Investment Goal

The Fund’s primary investment goal is to provide a level of current income which exceeds the average yield on U.S. stocks generally, and which will generally grow, subject to periodic fluctuations, over the years on a per share basis.

The Fund’s secondary investment goal is long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Investment Income Builder Fund
Thornburg Investment Income Builder Fund - Class R3
Thornburg Investment Income Builder Fund - Class R4
Thornburg Investment Income Builder Fund - Class R5
Thornburg Investment Income Builder Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Investment Income Builder Fund
Thornburg Investment Income Builder Fund - Class R3
Thornburg Investment Income Builder Fund - Class R4
Thornburg Investment Income Builder Fund - Class R5
Thornburg Investment Income Builder Fund - Class R6
Management Fees 0.70% 0.70% 0.70% 0.70%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses [1] 0.38% 0.51% 0.39% 0.14%
Acquired Fund Fees and Expenses 0.05% 0.05% 0.05% 0.05%
Total Annual Fund Operating Expenses 1.63% 1.51% 1.14% 0.89%
Fee Waiver/Expense Reimbursement [2] (0.08%) (0.06%) (0.10%) (0.04%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement [3] 1.55% 1.45% 1.04% 0.85%
[1] European Union tax reclaim collection fees are considered extraordinary expenses and are excluded from the Fund’s Other Expenses. If such fees were included, the Fund’s Other Expenses for Classes R3, R4, R5, and R6 would have been 0.51%, 0.64%, 0.52% and 0.27%, respectively.
[2] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, Class R5, and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.50%, 1.40%, 0.99%, and 0.80% respectively, not including the effects of Acquired Fund Fees and Expenses. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
[3] The figures for Total Fund Operating Expenses After Fee Waiver/Expense Reimbursement in this table have been recalculated to add amounts for “Acquired Fund Fees and Expenses,” in accordance with regulatory rules. Acquired Fund Fees and Expenses vary with changes in the amount of the Fund’s investments in investment companies and other factors. Please see the disclosure under the caption “Explanation of Acquired Fund Fees and Expenses” for a further explanation.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Investment Income Builder Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Investment Income Builder Fund - Class R3 158 506 879 1,926
Thornburg Investment Income Builder Fund - Class R4 148 471 818 1,796
Thornburg Investment Income Builder Fund - Class R5 106 352 618 1,377
Thornburg Investment Income Builder Fund - Class R6 87 280 489 1,092
Explanation of Acquired Fund Fees and Expenses.

“Acquired Fund Fees and Expenses” shown in the Annual Fund Operating Expenses table are expenses incurred indirectly by other investment companies, such as business development companies, in which the Fund may hold shares. These operating expenses are similar to the expenses paid by other businesses owned by the Fund, are not direct costs paid by Fund shareholders, and are not used to calculate the Fund’s net asset value. These expenses have no impact on the costs associated with Fund operations. Regulatory rules require that the Acquired Fund Fees and Expenses be added to the actual operating expenses of the Fund, and that the total be shown in the bottom line of the Annual Fund Operating Expenses table. Please see the expense figures shown in the Financial Highlights for the Fund, at pages 96–97, for a clearer picture of the Fund’s actual operating costs.

Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18.99% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goals by investing in a broad range of income producing securities, primarily including stocks and bonds, as described below. The Fund will under normal conditions invest at least 80% of its assets in income-producing securities, and at least 50% of its assets in common stocks.

The Fund may invest in any stock or other equity security which the investment advisor believes may assist the Fund in pursuing its investment goals (including smaller companies with market capitalization of less than $500 million and companies in developing countries), including preferred stock and publicly traded real estate investment trusts. The Fund expects that equity investments in the Fund’s portfolio normally will be weighted in favor of companies which pay dividends or other current income.

The Fund may invest in debt obligations of any kind, including corporate bonds and other obligations, mortgage- and other asset-backed securities and government obligations. The Fund may purchase debt obligations of any maturity and of any credit quality, including “high yield” or “junk” bonds. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics, such as convertible bonds.

The Fund may invest a significant portion of its assets in securities of issuers domiciled in or economically tied to countries outside the United States, including developing countries.

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund

may dispose of any such security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or otherwise to respond to market conditions.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.

Equity Risk – The value of the Fund’s equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

Risks Affecting Specific Issuers – The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Credit Risk – If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. The inability of an issuer to pay principal and interest on its debt obligations when due, or the downgrading of an issuer’s debt obligations by ratings agencies, may adversely affect the market’s perceptions of the issuer’s financial strength and may therefore result in declines in the issuer’s stock price.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments in debt obligations may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Foreign Investment Risk – Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Risks Affecting Specific Countries or Regions – If a significant portion of the Fund’s assets is invested in issuers that are economically exposed to one country or region, the Fund’s share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund’s ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund’s exposure to any such country or region, is expected to vary over time.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices.

Real Estate Risk – The Fund’s investments in publicly traded real estate investment trusts (“REITs”) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Income Builder Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares vary in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to a Blended Benchmark, comprised of 25% Bloomberg Barclays US Aggregate Bond Total Return Value USD, which represents a broad measure of bond market performance, and 75% MSCI World Net Total Return USD Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

15.81%

12/31/2020

Lowest Quarterly Results

(26.02)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Investment Income Builder Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Investment Income Builder Fund - Class R3 19.59% 8.59% 7.65%    
Thornburg Investment Income Builder Fund - Class R3 | After Taxes on Distributions 17.25% 6.72% 5.77%    
Thornburg Investment Income Builder Fund - Class R3 | After Taxes on Distributions and Sales 11.53% 5.81% 5.14%    
Thornburg Investment Income Builder Fund - Class R3 | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%    
Thornburg Investment Income Builder Fund - Class R4 19.69% 8.69% 7.75%    
Thornburg Investment Income Builder Fund - Class R4 | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%    
Thornburg Investment Income Builder Fund - Class R5 20.18% 9.13% 8.19%    
Thornburg Investment Income Builder Fund - Class R5 | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64% 12.30% 10.36%    
Thornburg Investment Income Builder Fund - Class R6 20.38%     9.12% Apr. 10, 2017
Thornburg Investment Income Builder Fund - Class R6 | Blended Index (reflects no deduction for fees, expenses, or U.S. taxes) 15.64%     11.95%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Limited Term U.S. Government Fund
Limited Term U.S. Government Fund
Investment Goal

The primary goal of Limited Term U.S. Government Fund is to provide as high a level of current income as is consistent, in the view of the Fund’s investment advisor, with safety of capital.

As a secondary goal, the Fund seeks to reduce changes in its share price compared to longer term portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Limited Term U.S. Government Fund
Thornburg Limited Term U.S. Government Fund - Class R3
Thornburg Limited Term U.S. Government Fund - Class R4
Thornburg Limited Term U.S. Government Fund - Class R5
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Limited Term U.S. Government Fund
Thornburg Limited Term U.S. Government Fund - Class R3
Thornburg Limited Term U.S. Government Fund - Class R4
Thornburg Limited Term U.S. Government Fund - Class R5
Management Fees 0.37% 0.37% 0.37%
Distribution and Service (12b-1) Fees 0.50% 0.25% none
Other Expenses 0.44% 1.01% 1.19%
Total Annual Fund Operating Expenses 1.31% 1.63% 1.56%
Fee Waiver/Expense Reimbursement [1] (0.32%) (0.64%) (0.89%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.99% 0.99% 0.67%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, and Class R5 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.99%, 0.99%, and 0.67%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Limited Term U.S. Government Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Limited Term U.S. Government Fund - Class R3 101 384 688 1,551
Thornburg Limited Term U.S. Government Fund - Class R4 101 452 826 1,879
Thornburg Limited Term U.S. Government Fund - Class R5 68 405 766 1,781
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 9.50% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio in pursuing the Fund’s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund’s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security before its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or to otherwise respond to market conditions.

Limited Term U.S. Government Fund invests at least 80% of its assets in U.S. Government Securities. For this purpose, “U.S. Government Securities” means:

Securities backed by the full faith and credit of the U.S. government, including direct obligations of the U.S. Treasury (such as U.S. Treasury Bonds) and obligations of U.S. government agencies and instrumentalities which are guaranteed by the U.S. Treasury (such as “Ginnie Mae” mortgage-backed certificates issued by the Government National Mortgage Association).

Securities issued or guaranteed by U.S. government agencies, instrumentalities or sponsored enterprises, but which are not backed by the full faith and credit of the U.S. government. These securities include mortgage-backed certificates, collateralized mortgage obligations (“CMOs”), and debentures issued by “Freddie Mac” (Federal Home Loan Mortgage Corporation) and “Fannie Mae” (Federal National Mortgage Association).

U.S. Government Securities include for this purpose repurchase agreements secured by the securities described above, and participations having economic characteristics similar to those securities. “Participations” are undivided interests in pools of securities where the underlying credit support passes through to the participants.

Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund’s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund’s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed securities.

Credit Risk – All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund’s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government-sponsored enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund are rated “Aaa” by Moody’s Investors Services or “AA+” by S&P Global Ratings. Ratings agencies may reduce the ratings of any securities in the future.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term U.S. Government Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3, Class R4, and Class R5 share performance to the Bloomberg Barclays US Government Intermediate Total Return Index Value Unhedged, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

1.84%

3/31/2020

Lowest Quarterly Results

(1.71)%

3/31/2021

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Limited Term U.S. Government Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Limited Term U.S. Government Fund - Class R3 (1.94%) 1.28% 0.97%    
Thornburg Limited Term U.S. Government Fund - Class R3 | After Taxes on Distributions (2.38%) 0.69% 0.29%    
Thornburg Limited Term U.S. Government Fund - Class R3 | After Taxes on Distributions and Sales (1.15%) 0.73% 0.45%    
Thornburg Limited Term U.S. Government Fund - Class R3 | Bloomberg Barclays Intermediate Government Bond Index (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32% 1.68%    
Thornburg Limited Term U.S. Government Fund - Class R4 (1.95%) 1.28%   1.11% Feb. 01, 2014
Thornburg Limited Term U.S. Government Fund - Class R4 | Bloomberg Barclays Intermediate Government Bond Index (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32%   1.96%  
Thornburg Limited Term U.S. Government Fund - Class R5 (1.63%) 1.62%   1.26% May 01, 2012
Thornburg Limited Term U.S. Government Fund - Class R5 | Bloomberg Barclays Intermediate Government Bond Index (reflects no deduction for fees, expenses, or taxes) (1.69%) 2.32%   1.69%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Limited Term Income Fund
Limited Term Income Fund
Investment Goal

The primary goal of Limited Term Income Fund is to provide as high a level of current income as is consistent, in the view of the Fund’s investment advisor, with safety of capital.

As a secondary goal, the Fund seeks to reduce changes in its share prices compared to longer term portfolios.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Limited Term Income Fund
Thornburg Limited Term Income Fund - Class R3
Thornburg Limited Term Income Fund - Class R4
Thornburg Limited Term Income Fund - Class R5
Thornburg Limited Term Income Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Limited Term Income Fund
Thornburg Limited Term Income Fund - Class R3
Thornburg Limited Term Income Fund - Class R4
Thornburg Limited Term Income Fund - Class R5
Thornburg Limited Term Income Fund - Class R6
Management Fees 0.31% 0.31% 0.31% 0.31%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses 0.21% 0.63% 0.38% 0.12%
Total Annual Fund Operating Expenses 1.02% 1.19% 0.69% 0.43%
Fee Waiver/Expense Reimbursement [1] (0.03%) (0.20%) (0.20%) (0.01%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 0.99% 0.99% 0.49% 0.42%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, Class R5, and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 0.99%, 0.99%, 0.49%, and 0.42%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Limited Term Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Limited Term Income Fund - Class R3 101 322 560 1,245
Thornburg Limited Term Income Fund - Class R4 101 358 635 1,425
Thornburg Limited Term Income Fund - Class R5 50 201 364 840
Thornburg Limited Term Income Fund - Class R6 43 137 240 541
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 33.37% of the average value of its portfolio.

Principal Investment Strategies

Thornburg Investment Management, Inc. (“Thornburg”) actively manages the Fund’s portfolio in pursuing the Fund’s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund’s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio’s average maturity, or to otherwise respond to current market conditions.

The Fund invests at least 65% of its net assets in (i) obligations of the U.S. government, its agencies and instrumentalities, and (ii) debt obligations rated at the time of purchase in one of the three highest principal long term rating categories of S&P Global Ratings (AAA, AA or A) or Moody’s Investors Services, Inc. (Aaa, Aa or A), or the equivalent three highest short term ratings of those ratings agencies, or, if no credit rating is available, judged to be of comparable quality as determined by Thornburg. The Fund will not invest in any debt obligation rated at the time of purchase lower than BBB by S&P, Baa by Moody’s, the of equivalent short term ratings of those ratings agencies, or, if no credit rating is available, judged to be of comparable quality as determined by Thornburg. The Fund may purchase debt obligations such as corporate debt obligations, mortgage-backed securities, other asset-backed securities, municipal securities, and commercial paper and bankers’ acceptances. The Fund may purchase foreign securities of the same types and quality as the domestic securities it purchases when Thornburg believes these investments are consistent with the Fund’s objectives.

Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms given an equivalent change in interest rates, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life normally of less than five years. As a result, the Fund also maintains a portfolio of investments having a dollar-weighted average effective duration of normally no more than five years. Duration is a measure of estimated sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. Duration is commonly expressed as a number, which is the expected percentage change in an obligation’s price upon a 1% change in interest rates. For example, an obligation with a duration of 5 would be expected to change in price by approximately 5% in response to a 1% change in interest rates. During temporary periods the Fund’s portfolio maturity and average effective duration may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund’s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund’s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund’s investment in mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Credit Risk – All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund’s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government sponsored enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund, are rated “Aaa” by Moody’s Investors Services or “AA+” by S&P Global Ratings. Ratings agencies may reduce the ratings of any securities in the future. Lower-rated or unrated obligations in which the Fund is permitted to invest may have, or may be perceived to have, greater risk of default and ratings downgrades.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.

Risks Affecting Specific Issuers – The value of a debt obligation may decline in response to developments affecting the specific issuer of the obligation, even if other issuers or the overall economy are unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Foreign Investment Risk – Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell promptly some or all of the obligations that it holds, or may only be able to sell obligations at less than desired prices.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Limited Term Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the Bloomberg Barclays Intermediate US Government/Credit Total Return Index Value Unhedged, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

5.66%

6/30/2020

Lowest Quarterly Results

(2.08)%

6/30/2013

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Limited Term Income Fund
1 Year
5 Years
10 Years
Since Inception
Inception Date
Thornburg Limited Term Income Fund - Class R3 (1.30%) 2.75% 2.74%    
Thornburg Limited Term Income Fund - Class R3 | After Taxes on Distributions (1.73%) 1.85% 1.78%    
Thornburg Limited Term Income Fund - Class R3 | After Taxes on Distributions and Sales (0.77%) 1.72% 1.70%    
Thornburg Limited Term Income Fund - Class R3 | Bloomberg Barclays Intermediate Government/Credit Index (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91% 2.38%    
Thornburg Limited Term Income Fund - Class R4 (1.30%) 2.75%   2.41% Feb. 01, 2014
Thornburg Limited Term Income Fund - Class R4 | Bloomberg Barclays Intermediate Government/Credit Index (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91%   2.51%  
Thornburg Limited Term Income Fund - Class R5 (0.80%) 3.20%   2.92% May 01, 2012
Thornburg Limited Term Income Fund - Class R5 | Bloomberg Barclays Intermediate Government/Credit Index (reflects no deduction for fees, expenses, or taxes) (1.44%) 2.91%   2.31%  
Thornburg Limited Term Income Fund - Class R6 (0.73%)     3.42% Apr. 10, 2017
Thornburg Limited Term Income Fund - Class R6 | Bloomberg Barclays Intermediate Government/Credit Index (reflects no deduction for fees, expenses, or taxes) (1.44%)     2.88%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.

Retirement | Thornburg Strategic Income Fund
Strategic Income Fund
Investment Goal

The Fund’s primary investment goal is to seek a high level of current income.

The Fund’s secondary investment goal is some long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)
Shareholder Fees - Retirement - Thornburg Strategic Income Fund
Thornburg Strategic Income Fund - Class R3
Thornburg Strategic Income Fund - Class R4
Thornburg Strategic Income Fund - Class R5
Thornburg Strategic Income Fund - Class R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) none none none none
Maximum Deferred Sales Charge (Load) (as a percentage of redemption proceeds or original purchase price, whichever is lower) none none none none
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Annual Fund Operating Expenses - Retirement - Thornburg Strategic Income Fund
Thornburg Strategic Income Fund - Class R3
Thornburg Strategic Income Fund - Class R4
Thornburg Strategic Income Fund - Class R5
Thornburg Strategic Income Fund - Class R6
Management Fees 0.60% 0.60% 0.60% 0.60%
Distribution and Service (12b-1) Fees 0.50% 0.25% none none
Other Expenses 2.06% 1.43% 0.32% 0.15%
Total Annual Fund Operating Expenses 3.16% 2.28% 0.92% 0.75%
Fee Waiver/Expense Reimbursement [1] (1.91%) (1.03%) (0.32%) (0.22%)
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement 1.25% 1.25% 0.60% 0.53%
[1] Thornburg Investment Management, Inc. (“Thornburg”) has contractually agreed to waive fees and reimburse expenses incurred by the Fund so that actual Class R3, Class R4, Class R5 and Class R6 expenses (excluding taxes, interest expenses, 12b-1 distribution and service fees, acquired fund fees and expenses, brokerage commissions, borrowing costs, expenses relating to short sales, and unusual expenses such as contingency fees or litigation costs) do not exceed 1.25%, 1.25%, 0.60%, and 0.53%, respectively. The agreement to waive fees and reimburse expenses may be terminated by the Fund’s Trustees at any time, but may not be terminated by Thornburg before February 1, 2023, unless Thornburg ceases to be the investment advisor of the Fund prior to that date. Thornburg may recoup amounts waived or reimbursed during the Fund’s fiscal year if actual expenses fall below the expense cap during that same fiscal year.
Example.

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:

Expense Example - Retirement - Thornburg Strategic Income Fund - USD ($)
Expense Example, with Redemption, 1 Year
Expense Example, with Redemption, 3 Years
Expense Example, with Redemption, 5 Years
Expense Example, with Redemption, 10 Years
Thornburg Strategic Income Fund - Class R3 127 795 1,488 3,334
Thornburg Strategic Income Fund - Class R4 127 613 1,126 2,536
Thornburg Strategic Income Fund - Class R5 61 261 478 1,102
Thornburg Strategic Income Fund - Class R6 54 218 395 910
Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over”) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 28.55% of the average value of its portfolio.

Principal Investment Strategies

The Fund pursues its investment goals by investing in a broad range of income-producing investments from throughout the world, primarily including debt obligations. The Fund expects, under normal conditions, to invest a majority of its assets in the debt obligations described below.

The Fund may invest in debt obligations of any kind, of any quality, and of any maturity. The Fund expects, under normal conditions, to select a majority of its investments from among the following types of debt obligations:

bonds and other debt obligations issued by domestic and foreign companies of any size (including lower-rated “high yield” or “junk” bonds)

mortgage-backed securities and other asset-backed securities, including commercial mortgage-backed securities

convertible debt obligations

obligations issued by foreign governments (including developing countries)

collateralized mortgage obligations (“CMOs”), collateralized debt obligations (“CDOs”), collateralized bond obligations (“CBOs”), and collateralized loan obligations (“CLOs”)

obligations of the U.S. government and its agencies and sponsored enterprises

structured notes

zero coupon bonds and “stripped” securities

taxable municipal obligations and participations in municipal obligations

The Fund’s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt securities, and analysis of specific issuers.

The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may sell an investment prior to its scheduled maturity date to enhance income or reduce loss, to change the portfolio’s average duration or average maturity, to pursue other investment opportunities, in response to changes in the conditions or business of the investment’s issuer or changes in overall market conditions, or if, in Thornburg’s opinion, the investment no longer serves to achieve the Fund’s investment goals. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.

Principal Investment Risks

An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund’s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund’s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.

Management Risk – The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.

Interest Rate Risk – When interest rates increase, the value of the Fund’s investments may decline and the Fund’s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund’s dividends may decline.

Prepayment and Extension Risk – When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund’s investments in mortgage-backed and asset-backed securities.

Credit Risk – If obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund’s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. Debt obligations backed by so-called “subprime” mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as “agency obligations”) are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk.

High Yield Risk – Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as “junk” or “high yield” bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer’s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

Market and Economic Risk – The value of the Fund’s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments. The market value of any zero coupon bonds or “stripped” securities that the Fund may purchase will typically be more volatile than the value of a comparable, interest-paying bond. Additionally, zero coupon bonds and “stripped” securities are subject to the risk that the Fund may have to recognize income on its investment and make distributions to shareholders before it has received any cash payments on its investment.

Risks Affecting Specific Issuers – The value of a debt obligation may decline in response to developments affecting the specific issuer of the obligation or security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer’s competitive position.

Liquidity Risk – Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. The market for lower-rated and unrated debt obligations (including particularly “junk” or “high yield” bonds) and debt obligations backed by so-called “subprime” mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

Small and Mid-Cap Company Risk – Investments in small-capitalization companies and mid-capitalization companies may involve additional risks, which may be relatively higher with smaller companies. These additional risks may result from limited product lines, more limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling these investments.

Foreign Investment Risk – Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

Developing Country Risk – The risks which may affect investments in foreign issuers (see “Foreign Investment Risk,” above) may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts its business in developing countries.

Foreign Currency Risk – Fluctuations in currency exchange rates can adversely affect the value of the Fund’s foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government’s decision to devalue its currency or impose currency controls.

Structured Products Risk – Investments in securities that are backed by, or represent interests in, an underlying pool of securities or other assets, including investments in mortgage- and asset-backed securities and in collateralized mortgage obligations and collateralized debt obligations, involve the risks associated with the underlying assets (e.g., the risk of default by mortgagors whose mortgages are included in a mortgage-backed security or collateralized mortgage obligation), and may also involve different or greater risks, including the risk that distributions from the underlying assets will be inadequate to make interest or other payments to the Fund, the risk that the issuer of the securities will fail to administer the underlying assets properly or become insolvent, and the risk that the securities will be less liquid than other Fund investments.

Cybersecurity and Operational Risk – Operational failures, cyber-attacks or other disruptions that affect the Fund’s service providers, the Fund’s counterparties, other market participants or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.

Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 61 of the Prospectus.

Past Performance of the Fund

The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund’s investment results vary from year to year. The bar chart shows the annual total return for Class R3 shares in the one full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the Bloomberg Barclays US Universal Total Return Index Value Unhedged, a broad measure of market performance, and to a Blended Benchmark comprised of 80% Bloomberg Barclays US Aggregate Bond Total Return Value USD, which represents a broad measure of bond market performance, and 20% MSCI World Net Total Return USD Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2021. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.

Annual Total Returns – Class R3 Shares
Bar Chart

Total
Returns

Quarter
ended

Highest Quarterly Results

7.85%

6/30/2020

Lowest Quarterly Results

(5.71)%

3/31/2020

Average Annual Total Returns (periods ended 12-31-21)
Average Annual Total Returns - Retirement - Thornburg Strategic Income Fund
1 Year
5 Years
Since Inception
Inception Date
Thornburg Strategic Income Fund - Class R3 2.11% 4.55% 4.48% May 01, 2012
Thornburg Strategic Income Fund - Class R3 | After Taxes on Distributions 0.68% 3.20% 2.71%  
Thornburg Strategic Income Fund - Class R3 | After Taxes on Distributions and Sales 1.25% 2.91% 2.66%  
Thornburg Strategic Income Fund - Class R3 | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.79%  
Thornburg Strategic Income Fund - Class R3 | Bloomberg Barclays U.S. Universal Index (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.23%  
Thornburg Strategic Income Fund - Class R4 2.20% 4.55% 3.85% Feb. 01, 2014
Thornburg Strategic Income Fund - Class R4 | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.95%  
Thornburg Strategic Income Fund - Class R4 | Bloomberg Barclays U.S. Universal Index (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.50%  
Thornburg Strategic Income Fund - Class R5 2.78% 5.20% 4.95% May 01, 2012
Thornburg Strategic Income Fund - Class R5 | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85% 5.97% 4.79%  
Thornburg Strategic Income Fund - Class R5 | Bloomberg Barclays U.S. Universal Index (reflects no deduction for fees, expenses, or taxes) (1.10%) 3.84% 3.23%  
Thornburg Strategic Income Fund - Class R6 2.85%   5.15% Apr. 10, 2017
Thornburg Strategic Income Fund - Class R6 | Blended Benchmark (reflects no deduction for fees, expenses, or U.S. taxes) 2.85%   5.87%  
Thornburg Strategic Income Fund - Class R6 | Bloomberg Barclays U.S. Universal Index (reflects no deduction for fees, expenses, or taxes) (1.10%)   3.77%  

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor’s own tax situation and may differ from the returns shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. The after-tax returns shown relate only to Class R3 shares, and after-tax returns for other share classes will vary.