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(Loomis Sayles High Income Fund)

Investment Goal

The Fund seeks high current income plus the opportunity for capital appreciation to produce a high total return.

Fund Fees & Expenses

The following table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in this table. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the Natixis Funds Complex. More information about these and other discounts is available from your financial professional and in the section "How Sales Charges Are Calculated" on page 75 of the Prospectus, in Appendix A to the Prospectus and on page 135 in the section "Reduced Sales Charges" of the Statement of Additional Information ("SAI").

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees - (Loomis Sayles High Income Fund) - USD ($)	Class A		Class C	Class N	Class T	Class Y
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	4.25%		none	none	2.50%	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	none	^[1]	1.00%	none	none	none
Redemption fees	none		none	none	none	none

[1]	A 1.00% contingent deferred sales charge ("CDSC") may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date 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 - (Loomis Sayles High Income Fund)		Class A	Class C	Class N	Class T		Class Y
Management fees		0.60%	0.60%	0.60%	0.60%		0.60%
Distribution and/or service (12b-1) fees		0.25%	1.00%	none	0.25%		none
Other expenses		0.33%	0.33%	0.22%	0.33%	^[1]	0.33%
Total annual fund operating expenses		1.18%	1.93%	0.82%	1.18%		0.93%
Fee waiver and/or expense reimbursement	^[2],[3]	0.18%	0.18%	0.12%	0.18%		0.18%
Total annual fund operating expenses after fee waiver and/or expense reimbursement		1.00%	1.75%	0.70%	1.00%		0.75%

[1]	Other expenses are estimated for the current fiscal year.
[2]	Loomis, Sayles & Company, L.P. ("Loomis Sayles" or the "Adviser") has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 1.00%, 1.75%, 0.70%, 1.00% and 0.75% of the Fund's average daily net assets for Class A, C, N, T and Y shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2021 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below the applicable expense limitations for Class A, C, N, T and Y shares. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.
[3]	Natixis Advisors, L.P. ("Natixis Advisors") has given a binding contractual undertaking to the Fund to reimburse any and all transfer agency expenses for Class N shares. This undertaking is in effect through April 30, 2021 and may be terminated before then only with the consent of the Fund's Board of Trustees.

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 (except where indicated). The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same, except that the example is based on the Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement assuming that such waiver and/or reimbursement will only be in place through the date noted above and on the Total Annual Fund Operating Expenses for the remaining periods. The example does not take into account brokerage commissions and other fees to financial intermediaries that you may pay on your purchases and sales of shares of the Fund. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

If shares are redeemed:

Expense Example - (Loomis Sayles High Income Fund) - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	523	767	1,030	1,781
Class C	278	589	1,025	2,239
Class N	72	250	443	1,002
Class T	349	598	866	1,630
Class Y	77	278	497	1,127

If shares are not redeemed:

Expense Example, No Redemption - (Loomis Sayles High Income Fund)	1 Year	3 Years	5 Years	10 Years
Class C \| USD ($)	178	589	1,025	2,239

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 for you if your 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 its most recently ended fiscal year, the Fund's portfolio turnover rate was 48% of the average value of its portfolio.

Investments, Risks and Performance Principal Investment Strategies

Under normal market conditions, the Fund will invest at least 80% of its assets in below investment grade fixed-income securities (commonly known as "junk bonds"). Below investment grade fixed-income securities are rated below investment grade quality (i.e., none of the three major ratings agencies (Moody's Investors Service, Inc. ("Moody's"), Fitch Investors Services, Inc. ("Fitch") or S&P Global Ratings ("S&P")), have rated the securities in one of its top four rating categories) or, if the security is unrated, are determined by the Adviser to be of comparable quality. There is no minimum rating for the securities in which the Fund may invest. The Fund may invest up to 30% of its assets in U.S. dollar-denominated foreign fixed-income securities, including those in emerging markets. Although certain securities purchased by the Fund may be issued by domestic companies incorporated outside of the United States, the Adviser does not consider these securities to be foreign if the issuer is included in the U.S. fixed-income indices published by Bloomberg Barclays.

The Adviser performs its own extensive credit analysis to determine the creditworthiness and potential for capital appreciation of a security. The Fund's management minimizes both market timing and interest rate forecasting. Instead, it uses a strategy based on gaining a thorough understanding of industry and company dynamics as well as individual security characteristics such as issuer debt and debt maturity schedules, earnings prospects, responsiveness to changes in interest rates, experience and perceived strength of management, borrowing requirements and liquidation value, market price in relation to cash flow, interest and dividends.

In deciding which securities to buy and sell, the Adviser will consider, among other things, the financial strength of the issuer, current interest rates, current valuations, the Adviser's expectations regarding future changes in interest rates and comparisons of the level of risk associated with particular investments with the Adviser's expectations concerning the potential return of those investments.

In selecting investments for the Fund, the Adviser utilizes the skills of its in-house team of more than 30 research analysts to cover a broad universe of industries, companies and markets. The Fund's portfolio managers take advantage of these extensive resources to identify securities that meet the Fund's investment criteria. The Adviser employs a selection strategy that focuses on a value-driven, bottom-up approach to identify securities that provide an opportunity for both generous yields and capital appreciation. The Adviser analyzes an individual company's potential for positive financial news to determine if it has growth potential. Examples of positive financial news include an upward turn in the business cycle, improvement in cash flows, rising profits or the awarding of new contracts. The Adviser emphasizes in-depth credit analysis, appreciation potential and diversification in its bond selection. Each bond is evaluated to assess the ability of its issuer to pay interest and, ultimately, principal (which helps the Fund generate an ongoing flow of income). The Adviser also assesses a bond's relation to market conditions within its industry and favors bonds whose prices may benefit from positive business developments. The Adviser seeks to diversify the Fund's holdings to reduce the inherent risk in below investment grade fixed-income securities.

In connection with its principal investment strategies, the Fund may also invest in structured notes, collateralized loan obligations, zero-coupon securities, pay-in-kind securities, convertible securities, securities issued pursuant to Rule 144A under the Securities Act of 1933 ("Rule 144A securities"), and futures, forward contracts and swaps (including credit default swaps) for hedging and investment purposes. Except as provided above or as required by applicable law, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Principal Investment Risks

The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program. You may lose money by investing in the Fund.

The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund's portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund.

Below Investment Grade Fixed-Income Securities Risk: The Fund's investments in below investment grade fixed-income securities, also known as "junk bonds," may be subject to greater risks than other fixed-income securities, including being subject to greater levels of interest rate risk, credit/counterparty risk (including a greater risk of default) and liquidity risk. The ability of the issuer to make principal and interest payments is predominantly speculative for below investment grade fixed-income securities.

Credit/Counterparty Risk: Credit/counterparty risk is the risk that the issuer or the guarantor of a fixed-income security, or the counterparty to a derivative or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risk with respect to the counterparties to its derivatives transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee given by a central clearing house, are not available in connection with over-the-counter ("OTC") derivatives transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivatives transactions, the Fund will be subject to the risk that its counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Market/Issuer Risk: The market value of the Fund's investments will move up and down, sometimes rapidly and unpredictably, based upon overall market and economic conditions, as well as a number of reasons that directly relate to the issuers of the Fund's investments, such as management performance, financial condition and demand for the issuers' goods and services.

Interest Rate Risk: Interest rate risk is the risk that the value of the Fund's investments will fall if interest rates rise. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise. Interest rate risk generally is greater for funds that invest in fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. The value of zero-coupon and pay-in-kind bonds may be more sensitive to fluctuations in interest rates than other fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect the market for these securities and reduce the Fund's ability to sell them, negatively impacting the performance of the Fund. Potential future changes in government monetary policy may affect the level of interest rates.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Decreases in the number of financial institutions willing to make markets in the Fund's investments or in their capacity or willingness to transact may increase the Fund's exposure to this risk. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. Securities acquired in a private placement, such as Rule 144A securities, are generally subject to significant liquidity risk because they are subject to strict restrictions on resale and there may be no liquid secondary market or ready purchaser for such securities. OTC derivatives are generally subject to liquidity risk as well. Liquidity issues may also make it difficult to value the Fund's investments.

Convertible Securities Risk

Convertible securities have investment characteristics of both equity and debt securities. Investments in convertible securities are subject to the usual risks associated with debt instruments, such as interest rate risk and credit risk. Convertible securities also react to changes in the value of the common stock into which they convert, and are thus subject to many of the same risks as investing in common stock. The Fund may also be forced to convert a convertible security at an inopportune time, which may decrease the Fund's return.

Cybersecurity and Technology Risk: The Fund, its service providers, and other market participants increasingly depend on complex information technology and communications systems, which are subject to a number of different threats and risks that could adversely affect the Fund and its shareholders. Cybersecurity and other operational and technology issues may result in financial losses to the Fund and its shareholders.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including futures, forward contracts, structured notes and swaps (including credit default swaps)) are subject to changes in the value of the underlying assets or indices on which such instruments are based. There is no guarantee that the use of derivatives will be effective or that suitable transactions will be available. Even a small investment in derivatives may give rise to leverage risk and can have a significant impact on the Fund's exposure to securities markets values, interest rates or currency exchange rates. It is possible that the Fund's liquid assets may be insufficient to support its obligations under its derivatives positions. The use of derivatives for other than hedging purposes may be considered a speculative activity, and involves greater risks than are involved in hedging. The use of derivatives may cause the Fund to incur losses greater than those that would have occurred had derivatives not been used. The Fund's use of derivatives, such as futures, forward contracts, structured notes and swaps (including credit default swaps) involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward currency contracts, swaps and other OTC derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate as expected with changes in the value of relevant assets, rates or indices, liquidity risk, allocation risk and the risk of losing more than the initial margin (if any) required to initiate derivatives positions. There is also the risk that the Fund may be unable to terminate or sell a derivative position at an advantageous time or price. The Fund's derivative counterparties may experience financial difficulties or otherwise be unwilling or unable to honor their obligations, possibly resulting in losses to the Fund.

Emerging Markets Risk: In addition to the risks of investing in foreign investments generally, emerging markets investments are subject to greater risks arising from political or economic instability, nationalization or confiscatory taxation, currency exchange restrictions, sanctions by other countries (such as the United States) and an issuer's unwillingness or inability to make principal or interest payments on its obligations. Emerging markets companies may be smaller and have shorter operating histories than companies in developed markets.

Foreign Securities Risk: Investments in foreign securities may be subject to greater political, economic, environmental, credit/counterparty and information risks. Foreign securities may be subject to higher volatility than U.S. securities, varying degrees of regulation and limited liquidity.

Leverage Risk: Use of derivative instruments may involve leverage. Leverage is the risk associated with securities or practices that multiply small index, market or asset-price movements into larger changes in value. The use of leverage increases the impact of gains and losses on the Fund's returns, and may lead to significant losses if investments are not successful.

Management Risk: A strategy used by the Fund's portfolio managers may fail to produce the intended result.

Mortgage-Related and Asset-Backed Securities Risk: In addition to the risks associated with investments in fixed-income securities generally (for example, credit, liquidity and valuation risk), mortgage-related and asset-backed securities are subject to the risks of the mortgages and assets underlying the securities as well as prepayment risk, the risk that the securities may be prepaid and result in the reinvestment of the prepaid amounts in securities with lower yields than the prepaid obligations. Conversely, there is a risk that a rise in interest rates will extend the life of a mortgage-related or asset-backed security beyond the expected prepayment time, typically reducing the security's value, which is called extension risk. The Fund also may incur a loss when there is a prepayment of securities that were purchased at a premium. The Fund's investments in other asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets.

Risk/Return Bar Chart and Table

The bar chart and table shown below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year-to-year and by showing how the Fund's average annual returns for the one-year, five-year, ten-year, and life-of-class periods (as applicable) compare to those of a broad measure of market performance. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available online at im.natixis.com and/or by calling the Fund toll-free at 800-225-5478.

The chart does not reflect any sales charge that you may be required to pay when you buy or redeem the Fund's shares. A sales charge will reduce your return.

Total Returns for Class Y Shares

Highest Quarterly Return:
First Quarter 2012, 9.74%

Lowest Quarterly Return:
Third Quarter 2011, -10.92%

Average Annual Total Returns (for the periods ended December 31, 2019)

Average Annual Total Returns - (Loomis Sayles High Income Fund)	Past 1 Year	Past 5 Years	Past 10 Years	Life of Class N	Inception Date
Class Y	12.52%	4.84%	6.56%
Class Y \| Return After Taxes on Distributions	10.17%	2.76%	3.89%
Class Y \| Return After Taxes on Distributions and Sale of Fund Shares	7.39%	2.77%	4.06%
Class A	7.11%	3.61%	5.79%
Class C	10.32%	3.76%	5.46%
Class N	12.28%			5.86%	Nov. 30, 2016
Class T	9.21%	3.98%	5.98%
Bloomberg Barclays U.S. Corporate High-Yield Bond Index	14.32%	6.13%	7.57%	6.80%	Nov. 30, 2016

The Fund did not have Class T shares outstanding during the periods shown above. The returns of Class T shares would have been substantially similar to the returns of the Fund's other share classes because they would have been invested in the same portfolio of securities and would only differ to the extent the other share classes did not have the same expenses. Performance of Class T shares shown above is that of Class A shares, which have the same expenses as Class T shares, restated to reflect the different sales load applicable to Class T shares.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans, qualified plans, education savings accounts, such as 529 plans, or individual retirement accounts. The after-tax returns are shown for only one class of the Fund. After-tax returns for the other classes of the Fund will vary. Index performance reflects no deduction for fees, expenses or taxes.

(Loomis Sayles Investment Grade Bond Fund)

Investment Goal

The Fund seeks high total investment return through a combination of current income and capital appreciation.

Fund Fees & Expenses

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees - (Loomis Sayles Investment Grade Bond Fund) - USD ($)	Class A		Class C	Class N	Class T	Class Y	Admin Class
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	4.25%		none	none	2.50%	none	none
Maximum deferred sales charge (load) (as a percentage of original purchase price or redemption proceeds, as applicable)	none	^[1]	1.00%	none	none	none	none
Redemption fees	none		none	none	none	none	none

[1]	A 1.00% contingent deferred sales charge ("CDSC") may apply to certain purchases of Class A shares of $1,000,000 or more that are redeemed within eighteen months of the date 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 - (Loomis Sayles Investment Grade Bond Fund)		Class A	Class C	Class N	Class T		Class Y	Admin Class
Management fees		0.40%	0.40%	0.40%	0.40%		0.40%	0.40%
Distribution and/or service (12b-1) fees		0.25%	1.00%	none	0.25%		none	0.25%
Other expenses		0.16%	0.16%	0.07%	0.16%	^[1]	0.16%	0.41%	^[2]
Total annual fund operating expenses		0.81%	1.56%	0.47%	0.81%		0.56%	1.06%
Fee waiver and/or expense reimbursement	^[3]	0.05%	0.05%	0.01%	0.05%		0.05%	0.05%
Total annual fund operating expenses after fee waiver and/or expense reimbursement		0.76%	1.51%	0.46%	0.76%		0.51%	1.01%

[1]	Other expenses are estimated for the current fiscal year.
[2]	Other expenses include an administrative services fee of 0.25% for Admin Class shares.
[3]	Loomis, Sayles & Company, L.P. ("Loomis Sayles" or the "Adviser") has given a binding contractual undertaking to the Fund to limit the amount of the Fund's total annual fund operating expenses to 0.76%, 1.51%, 0.46%, 0.76%, 0.51% and 1.01% of the Fund's average daily net assets for Class A, C, N, T, Y and Admin Class shares, respectively, exclusive of brokerage expenses, interest expense, taxes, acquired fund fees and expenses, organizational and extraordinary expenses, such as litigation and indemnification expenses. This undertaking is in effect through April 30, 2021 and may be terminated before then only with the consent of the Fund's Board of Trustees. The Adviser will be permitted to recover, on a class by class basis, management fees waived and/or expenses reimbursed to the extent that expenses in later periods fall below the applicable expense limitations for Class A, C, N, T, Y and Admin Class shares. The Fund will not be obligated to repay any such waived/reimbursed fees and expenses more than one year after the end of the fiscal year in which the fees or expenses were waived/reimbursed.

Example

If shares are redeemed:

Expense Example - (Loomis Sayles Investment Grade Bond Fund) - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	499	668	851	1,380
Class C	254	488	845	1,852
Class N	47	150	262	590
Class T	326	497	684	1,222
Class Y	52	174	308	697
Admin Class	103	332	580	1,290

If shares are not redeemed:

Expense Example, No Redemption - (Loomis Sayles Investment Grade Bond Fund)	1 Year	3 Years	5 Years	10 Years
Class C \| USD ($)	154	488	845	1,852

Portfolio Turnover

Investments, Risks and Performance Principal Investment Strategies

Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings made for investment purposes) in investment grade fixed-income securities (for example, bonds and other investments that the Adviser believes have similar economic characteristics, such as notes, debentures and loans). "Investment grade" securities are those securities that are rated in one of the top four categories at the time of purchase by at least one of the three major rating agencies — Moody's Investors Service, Inc. ("Moody's"), Fitch Investor Services, Inc. ("Fitch") or S&P Global Ratings ("S&P") or, if unrated, are determined by the Adviser to be of comparable quality. Although the Fund invests primarily in investment grade fixed-income securities, it may invest up to 15% of its assets in below investment grade fixed-income securities (also known as "junk bonds"). There is no minimum rating for the securities in which the Fund may invest. The Fund may invest in fixed-income securities of any maturity.

Three themes typically drive the Fund's investment approach. First, the Adviser generally seeks fixed-income securities of issuers whose credit profiles it believes are improving. Second, the Fund may invest significantly in securities the prices of which the Adviser believes are more sensitive to events related to the underlying issuer than to changes in general interest rates or overall market default rates. The Adviser believes that the Fund may generate positive returns by having a portion of the Fund's assets invested in non-market-related securities, rather than by relying primarily on changes in interest rates to produce returns for the Fund. Third, the Adviser analyzes different sectors of the economy and differences in the yields ("spreads") of various fixed-income securities in an effort to find securities that it believes may produce attractive returns for the Fund in comparison to their risk. The Adviser generally prefers securities that are protected against calls (early redemption by the issuer).

In connection with its principal investment strategies, the Fund may invest up to 30% of its assets in U.S. dollar-denominated foreign securities, including emerging markets securities. The Fund may also invest in U.S. dollar-denominated obligations of supranational entities without limit (e.g., the World Bank). Although certain securities purchased by the Fund may be issued by domestic companies incorporated outside of the United States, the Adviser does not consider these securities to be foreign if the issuer is included in the U.S. fixed-income indices published by Bloomberg Barclays. The Fund may also invest in corporate securities, U.S. government securities, commercial paper, zero-coupon securities, collateralized loan obligations, mortgage-backed securities, including mortgage dollar rolls, stripped mortgage-backed securities and collateralized mortgage obligations and other asset-backed securities, when-issued securities, convertible securities, securities issued pursuant to Rule 144A under the Securities Act of 1933 ("Rule 144A securities") and structured notes. The Fund may also invest in futures, forward contracts and swaps (including credit default swaps) for hedging and investment purposes. Except as provided above or as required by applicable law, the Fund is not limited in the percentage of its assets that it may invest in these instruments.

Principal Investment Risks

The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program. You may lose money by investing in the Fund.

Credit/Counterparty Risk: Credit/counterparty risk is the risk that the issuer or guarantor of a fixed-income security, or the counterparty to a derivative or other transaction, will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations. The Fund will be subject to credit risk with respect to the counterparties to its derivatives transactions. Many of the protections afforded to participants on organized exchanges, such as the performance guarantee given by a central clearing house, are not available in connection with over-the-counter ("OTC") derivatives transactions, such as foreign currency transactions. As a result, in instances when the Fund enters into OTC derivatives transactions, the Fund will be subject to the risk that its counterparties will not perform their obligations under the transactions and that the Fund will sustain losses or be unable to realize gains.

Interest Rate Risk: Interest rate risk is the risk that the value of the Fund's investments will fall if interest rates rise. Generally, the value of fixed-income securities rises when prevailing interest rates fall and falls when interest rates rise. Interest rate risk generally is greater for funds that invest in fixed-income securities with relatively longer durations than for funds that invest in fixed-income securities with shorter durations. The value of zero-coupon securities and securities with longer maturities are generally more sensitive to fluctuations in interest rates than other fixed-income securities. In addition, an economic downturn or period of rising interest rates could adversely affect the market for these securities and reduce the Fund's ability to sell them, negatively impacting the performance of the Fund. Potential future changes in government monetary policy may affect the level of interest rates.

Derivatives Risk: Derivative instruments (such as those in which the Fund may invest, including forward currency contracts, structured notes and swap transactions (including credit default swaps)) are subject to changes in the value of the underlying assets or indices on which such instruments are based. There is no guarantee that the use of derivatives will be effective or that suitable transactions will be available. Even a small investment in derivatives may give rise to leverage risk and can have a significant impact on the Fund's exposure to securities markets values, interest rates or currency exchange rates. It is possible that the Fund's liquid assets may be insufficient to support its obligations under its derivatives positions. The use of derivatives for other than hedging purposes may be considered a speculative activity, and involves greater risks than are involved in hedging. The use of derivatives may cause the Fund to incur losses greater than those that would have occurred had derivatives not been used. The Fund's use of derivatives, such as forward currency contracts, structured notes and swap transactions (including credit default swaps), involves other risks, such as the credit risk relating to the other party to a derivative contract (which is greater for forward currency contracts, swaps, and other OTC derivatives), the risk of difficulties in pricing and valuation, the risk that changes in the value of a derivative may not correlate as expected with changes in the value of relevant assets, rates or indices, liquidity risk, allocation risk and the risk of losing more than the initial margin (if any) required to initiate derivative positions. There is also the risk that the Fund may be unable to terminate or sell a derivatives position at an advantageous time or price. The Fund's derivative counterparties may experience financial difficulties or otherwise be unwilling or unable to honor their obligations, possibly resulting in losses to the Fund.

Management Risk: A strategy used by the Fund's portfolio managers may fail to produce the intended result.

Risk/Return Bar Chart and Table

The chart does not reflect any sales charge that you may be required to pay when you buy or redeem the Fund's shares. A sales charge will reduce your return.

Total Returns for Class Y Shares

Highest Quarterly Return:
Third Quarter 2010, 5.72%

Lowest Quarterly Return:
Second Quarter 2013, -3.16%

Average Annual Total Returns (for the periods ended December 31, 2019)

Average Annual Total Returns - (Loomis Sayles Investment Grade Bond Fund)	Past 1 Year	Past 5 Years	Past 10 Years		Life of Class N	Inception Date
Class Y	9.04%	3.16%	5.06%
Class Y \| Return After Taxes on Distributions	7.46%	1.70%	3.17%
Class Y \| Return After Taxes on Distributions and Sale of Fund Shares	5.33%	1.88%	3.25%
Class A	4.14%	2.01%	4.33%
Class C	6.94%	2.12%	4.01%
Class N	9.11%	3.25%			3.20%	Feb. 01, 2013
Class T	6.02%	2.39%	4.52%
Admin Class	8.43%	2.67%	4.54%	^[1]
Bloomberg Barclays U.S. Government/Credit Bond Index	9.71%	3.23%	3.96%		2.97%	Feb. 01, 2013

[1]	Prior to the inception of Admin Class shares (February 1, 2010), performance is that of Class A shares, restated to reflect the higher net expenses of Admin Class shares.