Summary Prospectus June 28, 2022 |  |
MFS®Government Securities Fund
Beforeyou invest, you may want to review the fund’s prospectus, which contains more information about the fund and its risks.You can find the fund’s prospectus and other information about the fund, including the fund’s reports to shareholders andstatement of additional information, online at funds.mfs.com. You can also get this information at no cost by calling 1-800-225-2606or by sending an e-mail request to orderliterature@mfs.com. The fund’s prospectus and statement of additional information, bothdated June 28, 2022, as may be amended or supplemented from time to time, are incorporated by reference into this summary prospectus.
| class | | ticker
symbol |
| Class A | | MFGSX |
| Class B | | MFGBX |
| Class C | | MFGDX |
| Class I | | MGSIX |
| Class R1 | | MFGGX |
| Class R2 | | MGVSX |
| Class R3 | | MFGHX |
| Class R4 | | MFGJX |
| Class R6 | | MFGKX |
Summaryof Key Information
InvestmentObjective
The fund’s investment objective is to seek total return withan emphasis on current income, but also considering capital appreciation.
Feesand Expenses
This table describes the fees and expenses that you may pay when youbuy, hold, and sell shares of the fund. Investors may also pay commissions or other fees to their financial intermediaries when theybuy, hold, and sell shares of the fund, which are not reflected below. Expenses have been adjusted to reflect current fee arrangements.
You may qualify for sales charge reductions if, with respect to Class Ashares, you and certain members of your family invest, or agree to invest in the future, at least $100,000 in MFS funds. More informationabout these and other waivers and reductions is available from your financial intermediary and in “Sales Charges and Waivers andReductions” on page 11 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of thefund’s prospectus.
Shareholder Fees (fees paid directly from your investment):
| Share Class | | A | | | B | | | C | | | I | | | R1 | | | R2 | | | R3 | | | R4 | | | R6 | |
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) | | | 4.25 | % | | | None | | | | None | | | | None | | | | None | | | | None | | | | None | | | | None | | | | None | |
| Maximum Deferred Sales Charge (Load) (as a percentage of original purchase price or redemption proceeds, whichever is less) | | | 1.00 | %# | | | 4.00 | % | | | 1.00 | % | | | None | | | | None | | | | None | | | | None | | | | None | | | | None | |
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
| Share Class | | A | | | B | | | C | | | I | | | R1 | | | R2 | | | R3 | | | R4 | | | R6 | |
| Management Fee | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % | | | 0.37 | % |
| Distribution and/or Service (12b-1) Fees | | | 0.25 | % | | | 1.00 | % | | | 1.00 | % | | | None | | | | 1.00 | % | | | 0.50 | % | | | 0.25 | % | | | None | | | | None | |
| Other Expenses | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.15 | % | | | 0.05 | % |
| Total Annual Fund Operating Expenses | | | 0.77 | % | | | 1.52 | % | | | 1.52 | % | | | 0.52 | % | | | 1.52 | % | | | 1.02 | % | | | 0.77 | % | | | 0.52 | % | | | 0.42 | % |
| Fee Reductions and/or Expense Reimbursements1 | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% | | | (0.01 | )% |
| Total Annual Fund Operating Expenses After Fee Reductions and/or Expense Reimbursements | | | 0.76 | % | | | 1.51 | % | | | 1.51 | % | | | 0.51 | % | | | 1.51 | % | | | 1.01 | % | | | 0.76 | % | | | 0.51 | % | | | 0.41 | % |
| # | This contingent deferred sales charge (CDSC) applies to shares purchased without an initial sales charge and redeemed within 18 months of purchase. |
| 1 | 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 June 30, 2023. |
MFG-SUM-062822
MFS Government Securities Fund
Example
This example is intended to help you compare the cost of investingin the fund with the cost of investing in other mutual funds.
The example assumes that: you invest $10,000 in the fund for the timeperiods indicated and you redeem your shares at the end of the time periods (unless otherwise indicated); your investment has a 5% returneach year; and the fund’s operating expenses remain the same.
Although your actual costs will likely be higher or lower, under theseassumptions your costs would be:
| | | 1 YEAR | | | 3 YEARS | | | 5 YEARS | | | 10 YEARS | |
| Class A Shares | | $ | 499 | | | $ | 660 | | | $ | 834 | | | $ | 1,338 | |
| Class B Shares assuming1 | | | | | | | | | | | | | | | | |
| redemption at end of period | | $ | 554 | | | $ | 779 | | | $ | 1,028 | | | $ | 1,609 | |
| no redemption at end of period | | $ | 154 | | | $ | 479 | | | $ | 828 | | | $ | 1,609 | |
| Class C Shares assuming1 | | | | | | | | | | | | | | | | |
| redemption at end of period | | $ | 254 | | | $ | 479 | | | $ | 828 | | | $ | 1,609 | |
| no redemption at end of period | | $ | 154 | | | $ | 479 | | | $ | 828 | | | $ | 1,609 | |
| Class I Shares | | $ | 52 | | | $ | 166 | | | $ | 290 | | | $ | 652 | |
| Class R1 Shares | | $ | 154 | | | $ | 479 | | | $ | 828 | | | $ | 1,812 | |
| Class R2 Shares | | $ | 103 | | | $ | 324 | | | $ | 562 | | | $ | 1,247 | |
| Class R3 Shares | | $ | 78 | | | $ | 245 | | | $ | 427 | | | $ | 953 | |
| Class R4 Shares | | $ | 52 | | | $ | 166 | | | $ | 290 | | | $ | 652 | |
| Class R6 Shares | | $ | 42 | | | $ | 134 | | | $ | 234 | | | $ | 529 | |
| 1 | Shares automatically convert to Class A shares approximately eight years after purchase; therefore, the expense examples reflect Class A share expenses after eight years. |
PortfolioTurnover
The fund pays transaction costs, such as commissions, when it buysand sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costsand may result in higher taxes when shares are held in a taxable account. These transaction costs, which are not reflected in “AnnualFund Operating Expenses” or in the “Example,” affect the fund’s performance. During the most recent fiscal year,the fund’s portfolio turnover rate was 398% of the average value of its portfolio.
PrincipalInvestment Strategies
MFS (Massachusetts Financial Services Company, the fund’s investmentadviser) normally invests at least 80% of the fund’s net assets in U.S. Government securities. MFS may also invest the fund's assetsin other debt instruments.
U.S. Government securities include mortgage-backed securities andother types of securitized instruments issued or guaranteed by the U.S. Treasury, by an agency or instrumentality of the U.S. Government,or by a U.S. Government-sponsored entity.
MFS generally invests substantially all of the fund’s assetsin investment grade quality debt instruments.
MFS may purchase or sell securities for the fund on a when-issued,delayed delivery, or forward commitment basis where payment and delivery take place at a future settlement date, including mortgage-backedsecurities purchased or sold in the to be announced (TBA) market.
MFS may invest the fund’s assets in foreign securities.
MFS may invest a significant percentage of the fund’s assetsin a single issuer or a small number of issuers.
MFS may engage in active and frequent trading in pursuing the fund’sprincipal investment strategies.
While MFS may use derivatives for any investment purpose, to the extentMFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of themarket, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivativesinclude futures, forward contracts, options, and swaps.
MFS uses an active bottom-up investment approach to buying and sellinginvestments 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 considerstop-down factors.
For purposes of the fund's 80% policy, net assets include the amountof any borrowings for investment purposes.
PrincipalRisks
As with any mutual fund, the fund may not achieve its objective and/oryou could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteedby the Federal Deposit Insurance Corporation or any other governmental agency.
The principal risks of investing in the fund are:
InvestmentSelection Risk: MFS' investment analysis and its selection of investments may not produce the intended results and/or canlead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperformingthe markets in which the fund invests.
DebtMarket Risk: Debt markets can be volatile and can decline significantly in response to, or investor perceptions of, issuer,market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditionscan affect a single instrument, issuer, or borrower, a particular type of instrument, issuer, or borrower, a segment of the debt marketsor the debt markets generally. Certain events can have a dramatic adverse effect on debt markets and may lead to periods of high volatilityand reduced liquidity in a debt market or segment of a debt market.
InterestRate Risk: 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 that do not pay current interest.
CreditRisk: The price of a debt instrument depends, in part, on the credit quality of the issuer, borrower, counterparty, or otherentity responsible for payment, or underlying collateral or assets and the terms of the instrument. The price of a debt instrument candecline 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.
U.S. Government securities not supported as to the payment of principalor interest by the U.S. Treasury are subject to greater credit risk than are U.S. Government securities supported by the U.S. Treasury.
Prepayment/ExtensionRisk: Instruments subject to prepayment and/or extension can reduce the potential for gain for the instrument’s holdersif the instrument is prepaid and increase the potential for loss if the maturity of the instrument is extended.
MFS Government Securities Fund
Inflation-AdjustedDebt Instruments Risk: Interest payments on inflation-adjusted debt instruments can be unpredictable and vary based on thelevel of inflation. If inflation is negative, principal and income can both decline.
ForeignRisk: Exposure to foreign markets through issuers or currencies can involve additional risks relating to market, economic,industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These factors can make foreign investments,especially those tied economically to emerging and frontier markets, more volatile and less liquid than U.S. investments. In addition,foreign markets can react differently to these conditions than the U.S. market.
FocusRisk: Issuers in a single country or region can react similarly to market, currency, political, economic, regulatory, geopolitical,environmental, public health, and other conditions, and the fund's performance will be affected by the conditions in the countries andregions to which the fund is exposed. If MFS invests a significant percentage of the fund's assets in a single issuer or small numberof issuers, the fund’s performance could be more volatile than the performance of more diversified funds.
DerivativesRisk: Derivatives can be highly volatile and involve risks in addition to the risks of the underlying indicator(s) onwhich the derivative is based. Gains or losses from derivatives can be substantially greater than the derivatives’ original cost.Derivatives can involve leverage.
When-Issued,Delayed Delivery, and Forward Commitment Transaction Risk: The purchaser in a when-issued, delayed delivery or forward commitmenttransaction assumes the rights and risks of ownership, including the risks of price and yield fluctuations and the risk that the securitywill not be issued or delivered as anticipated. When-issued, delayed delivery, and forward commitment transactions can involve leverage.
LeveragingRisk: Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatilityby magnifying gains or losses.
Counterpartyand Third Party Risk: Transactions involving a counterparty or third party other than the issuer of the instrument are subjectto the credit risk of the counterparty or third party, and to the counterparty’s or third party’s ability or willingnessto perform in accordance with the terms of the transaction.
LiquidityRisk: It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/orinvestments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that arenot advantageous in order to meet redemptions or other cash needs.
Activeand Frequent Trading Risk: Frequent trading increases transaction costs, which can reduce the fund's return, and can alsoincrease the possibility of capital gain and ordinary distributions. Frequent trading can also result in the realization of a higherpercentage of short-term capital gains and a lower percentage of long-term capital gains as compared to a fund that trades less frequently,which would generally increase your tax liability unless you hold your shares through a tax-advantaged or tax-exempt vehicle.
LargeShareholder Risk: 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 sellsecurities or invest additional cash, as the case may be, at disadvantageous prices. Redemptions of a large number of shares also mayincrease 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 cashand the fund maintains a larger cash position than it ordinarily would.
PerformanceInformation
The bar chart and performance table below are intended to providesome indication of the risks of investing in the fund by showing changes in the fund’s performance over time and how the fund’sperformance over time compares with that of a broad measure of market performance.
The fund’s past performance (before and after taxes) does notnecessarily indicate how the fund will perform in the future. Updated performance is available online at mfs.comor by calling 1-800-225-2606.
Class ABar Chart. The bar chart does not take into account any sales charges (loads) that you may be required to pay upon purchaseor redemption of the fund’s shares. If these sales charges were included, they would reduce the returns shown.
Thetotal return for the three-month period ended March 31, 2022, was (4.77)%. During the period(s) shown in the bar chart, thehighest quarterly return was 5.07% (for the calendar quarter ended March 31, 2020) and the lowest quarterly return was (3.24)% (forthe calendar quarter ended December 31, 2016).
MFSGovernment Securities Fund
Performance Table.
Average Annual Total Returns
(For the Periods Ended December 31, 2021)
| Share Class | | 1 YEAR | | | 5 YEARS | | | 10 YEARS | |
| Returns Before Taxes | | | | | | | | | | | | |
| B Shares | | | (6.79 | )% | | | 1.29 | % | | | 1.03 | % |
| C Shares | | | (3.88 | )% | | | 1.67 | % | | | 1.04 | % |
| I Shares | | | (1.94 | )% | | | 2.69 | % | | | 1.90 | % |
| R1 Shares | | | (2.92 | )% | | | 1.67 | % | | | 0.89 | % |
| R2 Shares | | | (2.43 | )% | | | 2.18 | % | | | 1.40 | % |
| R3 Shares | | | (2.18 | )% | | | 2.43 | % | | | 1.65 | % |
| R4 Shares | | | (1.94 | )% | | | 2.69 | % | | | 1.91 | % |
| R6 Shares | | | (1.83 | )% | | | 2.80 | % | | | 2.00 | % |
| A Shares | | | (6.34 | )% | | | 1.54 | % | | | 1.21 | % |
| Returns After Taxes on Distributions | | | | | | | | | | | | |
| A Shares | | | (6.73 | )% | | | 0.73 | % | | | 0.32 | % |
| Returns After Taxes on Distributions and Sale of Fund Shares | | | | | | | | | | | | |
| A Shares | | | (3.75 | )% | | | 0.82 | % | | | 0.53 | % |
| Index Comparison (Reflects no deduction for fees, expenses, or taxes) | | | | | | | | | | | | |
| Bloomberg U.S. Government/Mortgage Index | | | (1.77 | )% | | | 2.85 | % | | | 2.21 | % |
After-taxreturns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of stateand local taxes. Your actual after-tax returns will depend on your own tax situation, and may differ from those shown. The after-taxreturns shown are not relevant to investors who hold their shares through tax-advantaged arrangements, such as 401(k) plans or individualretirement accounts. The after-tax returns are shown for only one of the fund’s classes of shares, and after-tax returns for thefund’s other classes of shares will vary from the returns shown.
InvestmentAdviser
MFS serves as the investment adviser for the fund.
PortfolioManager(s)
| Portfolio Manager | | Since | | Title |
| Geoffrey Schechter | | 2006 | | Investment Officer of MFS |
| Jake Stone | | 2018 | | Investment Officer of MFS |
Purchaseand Sale of Fund Shares
You may purchase and redeem shares of the fund each day the New YorkStock Exchange (the NYSE) is open for trading. You may purchase or redeem shares either by having your financial intermediary processyour purchase or redemption, or through MFS Service Center, Inc. (MFSC) by overnight mail (MFSC, Suite 219341, 430 W 7thStreet, Kansas City, MO 64105-1407), by mail ([Fund Name], P.O. Box 219341, Kansas City, MO 64121-9341), by telephone(1-800-225-2606), or via the Internet at mfs.com(MFS Access).
The fund’s initial and subsequent investment minimums generallyare as follows:
| Class | | Initial Minimum | | Subsequent Minimum |
| Class A, Class B, Class C | | None – automatic investment plans and certain asset-based fee programs
$25 – employer-sponsored retirement plans
$250 – Traditional and Roth IRAs
$1,000 – other accounts | | $50 – by check and non-systematic written exchange request, and via MFSC telephone representatives
None – other purchases |
| Class I, Class R1, Class R2, Class R3, Class R4, Class R6 | | None | | None |
Purchases of Class B shares are closed to new and existing investorsexcept through reinvestment of dividends and capital gain distributions. Existing investors may continue to exchange their Class Bshares for the same share class of another MFS fund.
Taxes
If your shares are held in a taxable account, the fund’s distributionswill be taxed to you as ordinary income and/or capital gains. If your shares are held in a tax-advantaged account, you will generallybe taxed only upon withdrawals from the account.
Paymentsto Broker/Dealers and Other Financial Intermediaries
If you purchase shares of the fund through a broker/dealer or otherfinancial intermediary (such as a bank), the fund, MFS, and/or MFS’ affiliates may pay the financial intermediary for the saleof shares of the fund and/or the servicing of shareholder accounts. These payments may create a conflict of interest by influencing yourbroker/dealer or other financial intermediary and your salesperson to recommend the fund over another investment. Ask your financialintermediary or visit your financial intermediary’s website for more information.
