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cik0000751656:BloombergMunicipalBondIndex317Member 2025-03-31 2025-03-31 0000751656 cik0000751656:S000002528Summary16Member cik0000751656:S000002528Member cik0000751656:BloombergMunicipalBondIndex317Member 2024-01-01 2024-12-31 0000751656 cik0000751656:S000002528Summary16Member cik0000751656:S000002528Member cik0000751656:BloombergMunicipalBondIndex317Member 2020-01-01 2024-12-31 0000751656 cik0000751656:S000002528Summary16Member cik0000751656:S000002528Member cik0000751656:BloombergMunicipalBondIndex317Member 2015-01-01 2024-12-31 iso4217:USD pure utr:Y N-1A MFS® MUNICIPAL SERIES TRUST 2025-07-29 2025-07-29 MFS® Alabama Municipal Bond Fund Summary of Key Information MFALX MBABX MLALX MPOLX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Alabama, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0038 0.0038 0.0038 0.0032 0.0108 0.0183 0.0083 0.0077 -0.0018 -0.0018 -0.0018 -0.0018 0.0090 0.0165 0.0065 0.0059 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 513 737 978 1671 568 858 1174 1936 168 558 974 1936 66 247 443 1009 60 228 410 937 Portfolio Turnover <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 24% of the average value of its portfolio.</p> 0.24 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Alabama. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Alabama. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Alabama, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.43)%. During the period(s) shown in the bar chart, the highest quarterly return was 9.01% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.16)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0143 highest quarterly return 0.0901 2023-12-31 lowest quarterly return -0.0616 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0303 -0.0066 0.0117 0.0185 0.0070 0.0203 0.0191 0.0076 0.0208 -0.0276 -0.0043 0.0133 Returns After Taxes on Distributions -0.0280 -0.0045 0.0130 Returns After Taxes on Distributions and Sale of Fund Shares -0.0048 0.0019 0.0163 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Arkansas Municipal Bond Fund Summary of Key Information MFARX MBARX MARLX MPRAX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Arkansas, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0025 0.0025 0.0025 0.0018 0.0095 0.0170 0.0070 0.0063 -0.0025 -0.0025 -0.0010 -0.0010 0.0070 0.0145 0.0060 0.0053 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 493 691 905 1520 548 811 1100 1788 148 511 900 1788 61 214 380 861 54 192 341 777 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 15% of the average value of its portfolio.</p> 0.15 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund’s investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Arkansas. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Arkansas. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Arkansas, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.68)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.74% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.13)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0168 highest quarterly return 0.0874 2023-12-31 lowest quarterly return -0.0513 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0296 -0.0027 0.0125 0.0183 0.0097 0.0196 0.0190 0.0099 0.0201 -0.0258 -0.0003 0.0142 Returns After Taxes on Distributions -0.0261 -0.0005 0.0140 Returns After Taxes on Distributions and Sale of Fund Shares -0.0031 0.0057 0.0171 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® California Municipal Bond Fund Summary of Key Information MCFTX MBCAX MCCAX MCAVX MPOAX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of California, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 12 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0 0.0100 0.0400 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0.0100 0 0 0.0014 0.0014 0.0014 0.0014 0.0008 0.0084 0.0159 0.0159 0.0059 0.0053 -0.0019 -0.0019 -0.0004 -0.0004 -0.0004 0.0065 0.0140 0.0155 0.0055 0.0049 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 489 664 853 1401 543 783 1048 1672 143 483 848 1672 258 498 862 1685 158 498 862 1685 56 185 325 734 50 166 292 661 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.10 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of California. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of California. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in California, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (2.08)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.23% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.60)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0208 highest quarterly return 0.0823 2023-12-31 lowest quarterly return -0.0660 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0201 -0.0033 0.0183 0.0064 -0.0015 0.0172 0.0277 0.0084 0.0252 0.0283 0.0092 0.0259 -0.0164 -0.0009 0.0200 Returns After Taxes on Distributions -0.0168 -0.0012 0.0198 Returns After Taxes on Distributions and Sale of Fund Shares 0.0034 0.0056 0.0224 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Georgia Municipal Bond Fund Summary of Key Information MMGAX MBGAX MGATX MPGOX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Georgia, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0029 0.0029 0.0029 0.0023 0.0099 0.0174 0.0074 0.0068 -0.0009 -0.0009 -0.0009 -0.0008 0.0090 0.0165 0.0065 0.0060 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 513 718 940 1579 568 839 1135 1846 168 539 935 1846 66 228 403 910 61 210 371 839 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 20% of the average value of its portfolio.</p> 0.20 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Georgia. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Georgia. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Georgia, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.68)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.44% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.01)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0168 highest quarterly return 0.0844 2023-12-31 lowest quarterly return -0.0601 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0281 -0.0057 0.0115 0.0216 0.0080 0.0199 0.0222 0.0085 0.0204 -0.0242 -0.0033 0.0131 Returns After Taxes on Distributions -0.0245 -0.0034 0.0130 Returns After Taxes on Distributions and Sale of Fund Shares -0.0033 0.0025 0.0159 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Maryland Municipal Bond Fund Summary of Key Information MFSMX MBMDX MMDIX MPMDX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Maryland, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0031 0.0031 0.0031 0.0024 0.0101 0.0176 0.0076 0.0069 -0.0016 -0.0016 -0.0016 -0.0014 0.0085 0.0160 0.0060 0.0055 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 508 718 944 1595 563 839 1139 1862 163 539 939 1862 61 227 407 927 56 207 370 845 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.09 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Maryland. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Maryland. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Maryland, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.23)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.32% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.68)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0123 highest quarterly return 0.0832 2023-12-31 lowest quarterly return -0.0568 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0277 -0.0030 0.0134 0.0218 0.0109 0.0221 0.0224 0.0114 0.0226 -0.0239 -0.0003 0.0151 Returns After Taxes on Distributions -0.0242 -0.0005 0.0149 Returns After Taxes on Distributions and Sale of Fund Shares -0.0022 0.0054 0.0180 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Massachusetts Municipal Bond Fund Summary of Key Information MFSSX MBMAX MTALX MPMAX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Massachusetts, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0018 0.0018 0.0018 0.0010 0.0088 0.0163 0.0063 0.0055 -0.0006 -0.0006 -0.0006 -0.0005 0.0082 0.0157 0.0057 0.0050 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 505 688 886 1458 560 808 1081 1727 160 508 881 1727 58 196 345 781 51 171 302 684 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.10 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Massachusetts. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Massachusetts. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Massachusetts, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.51)%. During the period(s) shown in the bar chart, the highest quarterly return was 7.93% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.89)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0151 highest quarterly return 0.0793 2023-12-31 lowest quarterly return -0.0589 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0243 -0.0052 0.0128 0.0243 0.0085 0.0216 0.0251 0.0090 0.0220 -0.0214 -0.0028 0.0147 Returns After Taxes on Distributions -0.0216 -0.0031 0.0144 Returns After Taxes on Distributions and Sale of Fund Shares -0.0008 0.0034 0.0178 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Mississippi Municipal Bond Fund Summary of Key Information MISSX MBMSX MMSTX MPMSX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Mississippi, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0037 0.0037 0.0037 0.0031 0.0107 0.0182 0.0082 0.0076 -0.0031 -0.0041 -0.0016 -0.0016 0.0076 0.0141 0.0066 0.0060 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 499 721 961 1648 544 833 1147 1906 144 533 947 1906 67 246 439 999 61 227 407 927 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.16 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Mississippi. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Mississippi. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund is a non-diversified fund. This means that MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Mississippi, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Non-Diversification Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Because MFS may invest a significant percentage of the fund’s assets in a single issuer or small number of issuers, the fund’s performance could be closely tied to the value of that one issuer or issuers, and could be more volatile than the performance of diversified funds. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.22)%. During the period(s) shown in the bar chart, the highest quarterly return was 7.83% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.97)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0122 highest quarterly return 0.0783 2023-12-31 lowest quarterly return -0.0597 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0277 -0.0054 0.0115 0.0195 0.0057 0.0179 0.0200 0.0063 0.0183 -0.0248 -0.0039 0.0126 Returns After Taxes on Distributions -0.0252 -0.0041 0.0124 Returns After Taxes on Distributions and Sale of Fund Shares -0.0035 0.0025 0.0160 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Municipal Income Fund Summary of Key Information MFIAX MMIBX MMICX MIMIX MPMNX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0 0.0100 0.0400 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0036 0.0036 0.0036 0.0036 0.0036 0.0025 0.0100 0.0100 0 0 0.0016 0.0016 0.0016 0.0016 0.0009 0.0077 0.0152 0.0152 0.0052 0.0045 -0.0001 -0.0001 -0.0001 -0.0001 -0.0001 0.0076 0.0151 0.0151 0.0051 0.0044 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 499 660 834 1338 554 779 1028 1609 154 479 828 1609 254 479 828 1609 154 479 828 1609 52 166 290 652 45 143 251 566 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.09 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s total assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water, or sewers. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund's assets in issuers in a single state, territory, or possession, or a small number of states, territories, or possessions.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</span></p> <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s performance will be closely tied to the issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions in the states, territories, and possessions of the United States in which the fund's assets are invested. If MFS invests a significant percentage of the fund's assets in a single state, territory, or possession, or a small number of states, territories, or possessions, these conditions will have a significant impact on the fund's performance and the fund's performance may be more volatile than the performance of more geographically-diversified funds.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.29)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.40% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.58)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0129 highest quarterly return 0.0840 2023-12-31 lowest quarterly return -0.0658 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0135 -0.0010 0.0181 0.0164 0.0027 0.0180 0.0366 0.0126 0.0266 0.0373 0.0135 0.0272 -0.0099 0.0014 0.0197 Returns After Taxes on Distributions -0.0105 0.0010 0.0194 Returns After Taxes on Distributions and Sale of Fund Shares 0.0073 0.0071 0.0219 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Municipal Income Fund Summary of Key Information MMIDX MMIGX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in "Sales Charges and Waivers and Reductions" on page 10 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund's prospectus. </p> You may qualify for sales charge reductions if you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0.0100 0.0400 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0036 0.0036 0 0.0100 0.0016 0.0016 0.0052 0.0152 -0.0001 -0.0026 0.0051 0.0126 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 475 584 702 1049 528 755 1004 1519 128 455 804 1519 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.09 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s total assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water, or sewers. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund's assets in issuers in a single state, territory, or possession, or a small number of states, territories, or possessions.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s performance will be closely tied to the issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions in the states, territories, and possessions of the United States in which the fund's assets are invested. If MFS invests a significant percentage of the fund's assets in a single state, territory, or possession, or a small number of states, territories, or possessions, these conditions will have a significant impact on the fund's performance and the fund's performance may be more volatile than the performance of more geographically-diversified funds.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A1 Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.05)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.46% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.51)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0105 highest quarterly return 0.0846 2023-12-31 lowest quarterly return -0.0651 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes -0.0110 0.0015 0.0204 -0.0086 0.0039 0.0223 Returns After Taxes on Distributions -0.0092 0.0035 0.0220 Returns After Taxes on Distributions and Sale of Fund Shares 0.0091 0.0096 0.0244 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Municipal Intermediate Fund Summary of Key Information MIUAX MIUCX MIUIX MIURX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0035 0.0035 0.0035 0.0035 0.0025 0.0100 0 0 0.0024 0.0024 0.0024 0.0017 0.0084 0.0159 0.0059 0.0052 -0.0014 -0.0014 -0.0014 -0.0014 0.0070 0.0145 0.0045 0.0038 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 493 668 858 1406 248 488 852 1676 148 488 852 1676 46 175 315 725 39 153 277 639 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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% of the average value of its portfolio.</p> 0.18 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS normally invests at least 80% of the fund’s net assets in municipal instruments, the interest on which is exempt from U.S. federal income tax. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s dollar-weighted average effective maturity will normally range between three and ten years. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s total assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water, or sewers. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund's assets in issuers in a single state, territory, or possession, or a small number of states, territories, or possessions.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s performance will be closely tied to the issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions in the states, territories, and possessions of the United States in which the fund's assets are invested. If MFS invests a significant percentage of the fund's assets in a single state, territory, or possession, or a small number of states, territories, or possessions, these conditions will have a significant impact on the fund's performance and the fund's performance may be more volatile than the performance of more geographically-diversified funds.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of (i) a broad measure of market performance and (ii) the performance of an additional index that the adviser believes more closely reflects the market segments in which the fund invests.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of (i) a broad measure of market performance and (ii) the performance of an additional index that the adviser believes more closely reflects the market segments in which the fund invests. The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was 0.84%. During the period(s) shown in the bar chart, the highest quarterly return was 6.82% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.08)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 0.0084 highest quarterly return 0.0682 2023-12-31 lowest quarterly return -0.0508 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) 2021-05-18 2021-05-18 2021-05-18 2021-05-18 2021-05-18 2021-05-18 2021-05-18 2021-05-18 Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes 0.0099 -0.0045 0.0300 0.0054 0.0295 0.0057 -0.0172 -0.0090 Returns After Taxes on Distributions -0.0179 -0.0098 Returns After Taxes on Distributions and Sale of Fund Shares 0.0025 -0.0018 Reflects no deduction for fees, expenses, or taxes Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 -0.0019 Bloomberg Municipal 1-15 Year Index 0.0088 0.0012 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® New York Municipal Bond Fund Summary of Key Information MSNYX MBNYX MCNYX MNYLX MPNYX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of New York, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 12 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0 0.0100 0.0400 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0.0100 0 0 0.0026 0.0026 0.0026 0.0026 0.0018 0.0096 0.0171 0.0171 0.0071 0.0063 -0.0013 -0.0013 -0.0013 -0.0013 -0.0011 0.0083 0.0158 0.0158 0.0058 0.0052 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 506 705 921 1542 561 826 1116 1809 161 526 916 1809 261 526 916 1809 161 526 916 1809 59 214 382 870 53 191 340 776 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 12% of the average value of its portfolio.</p> 0.12 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of New York. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of New York. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in New York, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.96)%. During the period(s) shown in the bar chart, the highest quarterly return was 9.32% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.92)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0196 highest quarterly return 0.0932 2023-12-31 lowest quarterly return -0.0692 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0157 -0.0037 0.0152 0.0152 -0.0001 0.0151 0.0352 0.0099 0.0238 0.0359 0.0109 0.0243 -0.0120 -0.0013 0.0168 Returns After Taxes on Distributions -0.0120 -0.0015 0.0165 Returns After Taxes on Distributions and Sale of Fund Shares 0.0065 0.0052 0.0196 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® North Carolina Municipal Bond Fund Summary of Key Information MSNCX MBNCX MCNCX MNCLX MPNCX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of North Carolina, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 12 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0 0.0100 0.0400 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0.0100 0 0 0.0016 0.0016 0.0016 0.0016 0.0009 0.0086 0.0161 0.0161 0.0061 0.0054 -0.0002 -0.0002 -0.0002 -0.0002 -0.0002 0.0084 0.0159 0.0159 0.0059 0.0052 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 507 686 880 1439 562 806 1074 1708 162 506 874 1708 262 506 874 1708 162 506 874 1708 60 193 338 760 53 171 300 675 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 20% of the average value of its portfolio.</p> 0.20 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund’s investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of North Carolina. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of North Carolina. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in North Carolina, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.57)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.01% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.93)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0157 highest quarterly return 0.0801 2023-12-31 lowest quarterly return -0.0593 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0244 -0.0041 0.0125 0.0053 -0.0003 0.0124 0.0259 0.0096 0.0212 0.0267 0.0103 0.0216 -0.0206 -0.0015 0.0141 Returns After Taxes on Distributions -0.0208 -0.0017 0.0140 Returns After Taxes on Distributions and Sale of Fund Shares -0.0002 0.0043 0.0171 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Pennsylvania Municipal Bond Fund Summary of Key Information MFPAX MBPAX MPALX MPPAX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Pennsylvania, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0025 0.0025 0.0025 0.0018 0.0095 0.0170 0.0070 0.0063 -0.0026 -0.0026 -0.0011 -0.0011 0.0069 0.0144 0.0059 0.0052 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 492 690 904 1519 547 810 1099 1787 147 510 899 1787 60 213 379 860 53 191 340 776 Portfolio Turnover <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 19% of the average value of its portfolio.</p> 0.19 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund’s investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Pennsylvania. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Pennsylvania. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Pennsylvania, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.28)%. During the period(s) shown in the bar chart, the highest quarterly return was 7.70% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.79)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0128 highest quarterly return 0.0770 2023-12-31 lowest quarterly return -0.0579 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0176 -0.0019 0.0171 0.0308 0.0103 0.0241 0.0314 0.0108 0.0246 -0.0128 0.0007 0.0187 Returns After Taxes on Distributions -0.0131 0.0004 0.0185 Returns After Taxes on Distributions and Sale of Fund Shares 0.0051 0.0065 0.0212 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® South Carolina Municipal Bond Fund Summary of Key Information MFSCX MBSCX MTSCX MPOCX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of South Carolina, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 12 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0021 0.0021 0.0021 0.0014 0.0091 0.0166 0.0066 0.0059 -0.0007 -0.0007 -0.0007 -0.0006 0.0084 0.0159 0.0059 0.0053 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 507 696 901 1491 562 817 1096 1760 162 517 896 1760 60 204 361 816 54 183 323 732 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 19% of the average value of its portfolio.</p> 0.19 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of South Carolina. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of South Carolina. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in South Carolina, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.74)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.53% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (6.09)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0174 highest quarterly return 0.0853 2023-12-31 lowest quarterly return -0.0609 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0251 -0.0059 0.0112 0.0248 0.0076 0.0199 0.0254 0.0082 0.0202 -0.0213 -0.0035 0.0129 Returns After Taxes on Distributions -0.0216 -0.0037 0.0127 Returns After Taxes on Distributions and Sale of Fund Shares -0.0007 0.0026 0.0158 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® Virginia Municipal Bond Fund Summary of Key Information MSVAX MBVAX MVACX MIVAX MPVOX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of Virginia, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 12 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0 0.0100 0.0400 0.0100 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0.0100 0 0 0.0020 0.0020 0.0020 0.0020 0.0012 0.0090 0.0165 0.0165 0.0065 0.0057 -0.0008 -0.0008 -0.0008 -0.0008 -0.0007 0.0082 0.0157 0.0157 0.0057 0.0050 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 505 692 895 1479 560 813 1089 1748 160 513 889 1748 260 513 889 1748 160 513 889 1748 58 200 354 803 51 176 311 707 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 14% of the average value of its portfolio.</p> 0.14 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of Virginia. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of Virginia. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in Virginia, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">If MFS invests a significant percentage of the fund's assets in a single issuer or small number of issuers, the fund’s performance could be more volatile than the performance of more diversified funds. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.68)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.61% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.71)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0168 highest quarterly return 0.0861 2023-12-31 lowest quarterly return -0.0571 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0284 -0.0046 0.0130 0.0022 -0.0009 0.0129 0.0218 0.0090 0.0215 0.0225 0.0097 0.0221 -0.0246 -0.0021 0.0145 Returns After Taxes on Distributions -0.0247 -0.0024 0.0142 Returns After Taxes on Distributions and Sale of Fund Shares -0.0028 0.0042 0.0174 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown. MFS® West Virginia Municipal Bond Fund Summary of Key Information MFWVX MBWVX MWVIX MPWVX Investment Objective <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund’s investment objective is to seek total return with an emphasis on income exempt from U.S. federal income tax and personal income tax, if any, of West Virginia, but also considering capital appreciation. </p> Fees and Expenses <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> </span></p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More information about these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers and Reductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus. </p> You may qualify for sales charge reductions if, with respect to Class A shares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. 100000 Shareholder Fees (fees paid directly from your investment): 0.0425 0 0 0 0.0100 0.0400 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment): 0.0045 0.0045 0.0045 0.0045 0.0025 0.0100 0 0 0.0032 0.0032 0.0032 0.0025 0.0102 0.0177 0.0077 0.0070 -0.0015 -0.0015 -0.0015 -0.0015 0.0087 0.0162 0.0062 0.0055 Example <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% return each year; and the fund’s operating expenses remain the same. </p> Although your actual costs will likely be higher or lower, under these assumptions your costs would be: 510 722 950 1607 565 843 1145 1873 165 543 945 1873 63 231 413 940 56 209 375 856 Portfolio Turnover <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">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 shares are held in a taxable account. These transaction 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 12% of the average value of its portfolio.</p> 0.12 Principal Investment Strategies <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests the fund’s assets primarily in municipal instruments. Municipal instruments are debt instruments issued by or for states, territories, or possessions of the United States or by their political subdivisions, agencies, authorities, or other government entities, to raise money for a variety of public and private purposes, including general financing for state and local governments, or financing for a specific project or public facility. Municipal instruments include general obligation bonds of municipalities, state or local governments, project or revenue-specific bonds, municipal lease obligations, and pre-refunded or escrowed bonds. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax and personal income tax, if any, of West Virginia. However, interest from the fund’s investments may be subject to the U.S. federal alternative minimum tax. MFS may also invest the fund's assets in taxable instruments, including municipal instruments of other states.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS invests a significant percentage of the fund’s assets in municipal instruments of West Virginia. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS may invest 25% or more of the fund’s assets in municipal instruments that finance similar types of projects, such as those relating to education, healthcare, housing, utilities, water or sewers. Municipal instruments whose interest is exempt from U.S. federal and state personal income tax include instruments issued by U.S. territories and possessions (such as Puerto Rico, Guam, and the U.S. Virgin Islands) and their political subdivisions and public corporations. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS primarily invests the fund’s assets in investment grade quality debt instruments, but may also invest the fund’s assets in below investment grade quality debt instruments. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The fund is a non-diversified fund. This means that MFS may invest a significant percentage of the fund’s assets in a single issuer or a small number of issuers. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, inverse floating rate instruments, and swaps.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.</p> <p style="font-size:11.0pt; font-family:Arial; text-align:left; color:#000000; font-weight:bold; text-decoration:none;">Principal Risks </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The principal risks of investing in the fund are:</p> As with any mutual fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Investment Selection Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> MFS' investment analysis and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. In addition, to the extent MFS considers quantitative tools in managing the fund, such tools may not produce the intended results. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Debt Market Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Debt markets can be volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt markets or the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatility and reduced liquidity in a debt market or segment of a debt market. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Interest Rate Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">In general, the price of a debt instrument falls when interest rates rise and rises when interest rates fall. Interest rate risk is generally greater for instruments with longer maturities or durations, or that do not pay current interest.</span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Credit Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or other entity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument can decline in response to changes in, or perceptions of, the financial condition of the issuer, borrower, counterparty, or other entity, or underlying collateral or assets, or changes in, or perceptions of, specific or general market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. </span></p> <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Debt instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could negatively affect the market value and liquidity of a debt instrument.</p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The credit quality of, and the ability to pay principal and interest when due by, an issuer of a municipal instrument depends on the credit quality of the entity supporting the municipal instrument, how essential any services supported by the municipal instrument are, the sufficiency of any revenues or taxes that support the municipal instrument, and/or the willingness or ability of the appropriate government entity to approve any appropriations necessary to support the municipal instrument. In addition, the price of a municipal instrument also depends on its credit quality and ability to meet the credit support obligations of any insurer or other entity providing credit support to a municipal instrument. </p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p><p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">Below investment grade quality debt instruments (commonly referred to as “high yield securities” or “junk bonds”) can involve a substantially greater risk of default or can already be in default, and their values can decline significantly. Below investment grade quality debt instruments are regarded as having predominantly speculative characteristics. Below investment grade quality debt instruments tend to be more sensitive to adverse news about the issuer, or the market or economy in general, than higher quality debt instruments.</p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Focus Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> The fund’s performance will be closely tied to the economic, political, environmental, and public health conditions in West Virginia, and can be more volatile than the performance of a more geographically diversified fund. In addition, the fund's performance can also be tied to the economic and political conditions of other states and U.S. territories and possessions in which the fund is invested. These conditions may include constitutional or statutory limits on an issuer’s ability to raise revenues or increase taxes, anticipated or actual budget deficits or other financial difficulties, or changes in the credit quality of municipal issuers in the state, other states, or U.S. territories and possessions.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Non-Diversification Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Because MFS may invest a significant percentage of the fund’s assets in a single issuer or small number of issuers, the fund’s performance could be closely tied to the value of that one issuer or issuers, and could be more volatile than the performance of diversified funds. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Municipal Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The price of a municipal instrument can be volatile and significantly affected by adverse tax changes or court rulings, legislative or political changes, changes in specific or general market and economic conditions and developments, and the financial condition of municipal issuers and insurers. Because many municipal instruments are issued to finance similar projects, conditions in certain industries can significantly affect the fund and the overall municipal market. Municipal instruments may be more susceptible to downgrades or defaults during economic downturns or similar periods of economic stress, which in turn could affect the market values and marketability of many or all municipal obligations of issuers in a state, U.S. territory, or possession. </span></p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">In addition, because some municipal obligations may be secured or guaranteed by banks and other institutions, the risk associated with investments in such municipal securities could increase if the banking or financial sector suffers an economic downturn and/or if the credit ratings of the institutions issuing the guarantee are downgraded or at risk of being downgraded by a national rating organization. If such events occur, the value of the security could decrease or the value could be lost entirely, and it may be difficult or impossible to sell the security at the time and the price that normally prevails in the market. </p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Prepayment/Extension Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holders if the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Derivatives Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) on which the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost. Derivatives can involve leverage.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Leveraging Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Counterparty and Third Party Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Transactions involving a counterparty or third party other than the issuer of the instrument are subject to the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingness to perform in accordance with the terms of the transaction.</span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Liquidity Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:italic; color:#000000; font-weight:normal; text-decoration:none;"> </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs. </span></p> <p style="font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">Large Shareholder Risk: </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">From time to time, shareholders of the fund (which may include institutional investors, financial intermediaries, or other MFS funds) may make relatively large redemptions or purchases of fund shares. These transactions may cause the fund to sell securities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also may increase transaction and other costs or have adverse tax consequences for shareholders of the fund by requiring a sale of portfolio securities. Purchases of a large number of shares may adversely affect the fund's performance to the extent that it takes time to invest new cash and the fund maintains a larger cash position than it ordinarily would.</span></p> Performance Information <p style="font-size:10.0pt; font-family:Serif; font-style:normal; text-align:left; color:#000000; font-weight:normal; text-decoration:none;">The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that of a broad measure of market performance.</p><p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The fund’s past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future. Updated performance is available online at </span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:bold; text-decoration:none;">mfs.com</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;"> or by calling 1-800-225-2606.</span></p> The bar chart and performance table below are intended to provide some indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’s performance over time compares with that 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. mfs.com 1-800-225-2606 Class A Bar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchase or redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown. <p style="-sec-ix-redline:true;font-size:1.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">The total return for the six-month period ended June 30, 2025, was (1.45)%. During the period(s) shown in the bar chart, the highest quarterly return was 8.29% (for the calendar quarter ended December 31, 2023) and the lowest quarterly return was (5.03)% (for the calendar quarter ended March 31, 2022).</span></p> The total return for the six-month period ended 2025-06-30 -0.0145 highest quarterly return 0.0829 2023-12-31 lowest quarterly return -0.0503 2022-03-31 Performance Table. Average Annual Total Returns (For the Periods Ended December 31, 2024) Returns Before Taxes Returns Before Taxes Returns Before Taxes Returns Before Taxes -0.0275 -0.0032 0.0122 0.0229 0.0106 0.0208 0.0237 0.0114 0.0212 -0.0237 -0.0008 0.0138 Returns After Taxes on Distributions -0.0239 -0.0010 0.0136 Returns After Taxes on Distributions and Sale of Fund Shares -0.0023 0.0053 0.0169 Reflects no deduction for fees, expenses, or taxes Bloomberg Municipal Bond Index 0.0105 0.0099 0.0225 <p style="-sec-ix-redline:true;font-size:10.0pt; font-family:Serif; text-align:left; color:#000000; font-weight:normal; font-style:normal;"><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">Aft</span><span style="font-size:10.0pt; font-family:Serif; font-style:normal; color:#000000; font-weight:normal; text-decoration:none;">er-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for the fund’s other classes of shares will vary from the returns shown.</span></p> Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts (IRAs). 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oef_ClassAxis compact * row oef_PerformanceMeasureAxis compact * ~ ~ http://xbrl.sec.gov/rr/role/ShareholderFeesData row dei_DocumentInformationDocumentAxis compact cik0000751656_S000002528Summary16Member row dei_LegalEntityAxis compact cik0000751656_S000002528Member ~ ~ http://xbrl.sec.gov/rr/role/OperatingExpensesData row dei_DocumentInformationDocumentAxis compact cik0000751656_S000002528Summary16Member row dei_LegalEntityAxis compact cik0000751656_S000002528Member ~ ~ http://xbrl.sec.gov/rr/role/ExpenseExample row dei_DocumentInformationDocumentAxis compact cik0000751656_S000002528Summary16Member row dei_LegalEntityAxis compact cik0000751656_S000002528Member ~ ~ http://xbrl.sec.gov/rr/role/ExpenseExampleNoRedemption row dei_DocumentInformationDocumentAxis compact cik0000751656_S000002528Summary16Member row dei_LegalEntityAxis compact cik0000751656_S000002528Member ~ ~ http://xbrl.sec.gov/rr/role/PerformanceTableData column period compact * row dei_DocumentInformationDocumentAxis compact cik0000751656_S000002528Summary16Member row dei_LegalEntityAxis compact cik0000751656_S000002528Member row oef_ClassAxis compact * row oef_PerformanceMeasureAxis compact * ~ 0.0306 0.0024 0.0447 0.0103 0.0702 0.0404 0.0186 -0.1077 0.0642 0.0156 0.0305 0 0.0409 0.0123 0.0619 0.0424 0.0238 -0.0928 0.0585 0.0175 0.0456 0.0095 0.0614 0.0094 0.0833 0.04 0.0293 -0.1163 0.0697 0.0272 0.0272 0.0027 0.0432 0.0077 0.0694 0.0349 0.0201 -0.1025 0.0641 0.0191 0.0281 0.0063 0.0439 0.0128 0.064 0.0397 0.0255 -0.0994 0.0653 0.0194 0.0311 0.0038 0.0485 0.0076 0.0731 0.0368 0.0202 -0.1026 0.0614 0.022 0.0322 -0.0003 0.0406 0.0103 0.0656 0.0423 0.0195 -0.0982 0.0492 0.0185 0.0333 0.0099 0.0589 0.01 0.0814 0.0405 0.03 -0.1108 0.0672 0.034 0.037 0.0125 0.0603 0.0137 0.0829 0.0443 0.0326 -0.1084 0.0699 0.0354 -0.0741 0.0585 0.0264 0.0361 0.0035 0.0556 0.0058 0.0772 0.038 0.0296 -0.1233 0.0733 0.0319 0.0305 0.0021 0.0435 0.0069 0.0684 0.038 0.0216 -0.0974 0.0588 0.0228 0.0361 0.0109 0.0515 0.0143 0.074 0.0454 0.0264 -0.1021 0.0549 0.031 0.0315 -0.0011 0.0433 0.0102 0.0652 0.0404 0.0177 -0.1065 0.0614 0.0221 0.033 0.0049 0.0401 0.0123 0.0683 0.0439 0.0182 -0.0988 0.0588 0.0187 0.0285 0.0027 0.0398 0.0101 0.0625 0.0406 0.0204 -0.0936 0.0601 0.0196 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. July 31, 2026 July 31, 2026 July 31, 2026 July 31, 2026 ~ http://www.MFS.com/20250331/role/RRRiskTable3 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable5 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable7 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable9 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable11 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable13 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable15 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable17 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable19 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable21 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable23 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable25 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable27 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable29 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable31 ~ ~ http://www.MFS.com/20250331/role/RRRiskTable33 ~ This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.90% of the class' average daily net assets annually for Class A shares, 1.65% of the class' average daily net assets annually for Class B shares, 0.65% of the class' average daily net assets annually for Class I shares, and 0.59% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS Fund Distributors, Inc. (MFD), has agreed in writing to waive the Class A and Class B service fee to 0.10% of each class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.70% of the class' average daily net assets annually for Class A shares,1.45% of the class' average daily net assets annually for Class B shares, 0.60% of the class' average daily net assets annually for Class I shares, and 0.53% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS Fund Distributors, Inc. (MFD), has agreed in writing to waive the Class A and Class B service fee to 0.10% of each class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.65% of the class' average daily net assets annually for Class A shares, 1.40% of the class' average daily net assets annually for Class B shares, 1.55% of the class’ average daily net assets annually for Class C shares, 0.55% of the class' average daily net assets annually for Class I shares, and 0.49% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.90% of the class' average daily net assets annually for Class A shares, 1.65% of the class' average daily net assets annually for Class B shares, 0.65% of the class' average daily net assets annually for Class I shares, and 0.60% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.83% of the class' average daily net assets annually for Class A shares, 1.58% of the class' average daily net assets annually for Class B shares, 0.58% of the class' average daily net assets annually for Class I shares, and 0.53% of the class' average daily net assets annually for Class R6 shares. ("Other Expenses" include 0.02% of interest and/or investment-related expenses incurred in connection with the fund's investment activity which are excluded from the expense limitation described in the prior sentence.) This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.82% of the class' average daily net assets annually for Class A shares, 1.57% of the class' average daily net assets annually for Class B shares, 0.57% of the class' average daily net assets annually for Class I shares, and 0.50% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS Fund Distributors, Inc. (MFD), has agreed in writing to waive the Class A service fee to 0.10% of the class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. MFD has agreed in writing to waive the Class B service fee to 0.00% of the class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.76% of the class' average daily net assets annually for Class A shares, 1.41% of the class' average daily net assets annually for Class B shares, 0.66% of the class' average daily net assets annually for Class I shares, and 0.60% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS Fund Distributors, Inc. (MFD), has agreed in writing to waive the Class B1 service fee to 0.00% of the class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A1 shares approximately eight years after purchase; therefore, the expense examples reflect Class A1 share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.70% of the class' average daily net assets annually for Class A shares, 1.45% of the class' average daily net assets annually for Class C shares, 0.45% of the class' average daily net assets annually for Class I shares, and 0.38% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.83% of the class' average daily net assets annually for Class A shares,1.58% of the class' average daily net assets annually for each of Class B and Class C shares, 0.58% of the class' average daily net assets annually for Class I shares, and 0.52% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.84% of the class' average daily net assets annually for Class A shares, 1.59% of the class' average daily net assets annually for each of Class B and Class C shares, 0.59% of the class' average daily net assets annually for Class I shares, and 0.52% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS Fund Distributors, Inc. (MFD), has agreed in writing to waive the Class A and Class B service fee to 0.10% of each class' average daily net assets annually until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.69% of the class' average daily net assets annually for Class A shares, 1.44% of the class' average daily net assets annually for Class B shares, 0.59% of the class' average daily net assets annually for Class I shares, and 0.52% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund’s expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.84% of the class' average daily net assets annually for Class A shares, 1.59% of the class' average daily net assets annually for Class B shares, 0.59% of the class' average daily net assets annually for Class I shares, and 0.53% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund's expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.81% of the class' average daily net assets annually for Class A shares, 1.56% of the class' average daily net assets annually for each of Class B and Class C shares, 0.56% of the class' average daily net assets annually for Class I shares, and 0.49% of the class' average daily net assets annually for Class R6 shares. ("Other Expenses" include 0.01% of interest and/or investment-related expenses incurred in connection with the fund's investment activity which are excluded from the expense limitation described in the prior sentence.) This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. Massachusetts Financial Services Company (MFS) has agreed in writing to waive at least 0.01% of the fund's management fee as part of an agreement pursuant to which MFS has agreed to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least July 31, 2026. MFS has agreed in writing to bear the fund’s expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.87% of the class' average daily net assets annually for Class A shares, 1.62% of the class' average daily net assets annually for Class B shares, 0.62% of the class' average daily net assets annually for Class I shares, and 0.55% of the class' average daily net assets annually for Class R6 shares. This written agreement will continue until modified by the fund’s Board of Trustees, but such agreement will continue until at least July 31, 2026. Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years.