The fund’s investment objective is to seek total return.

This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. 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.

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 $50,000 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 13 and “Appendix A – Waivers and Reductions of Sales Charges” on page A-1 of the fund’s prospectus.

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 11% of the average value of its portfolio.

MFS (Massachusetts Financial Services Company, the fund's investment adviser) seeks to achieve the fund’s objective by generating returns from (1) a strategic allocation to three MFS equity funds, referred to as underlying funds, and (2) a tactical asset allocation overlay primarily using derivative instruments to seek to decrease the volatility of the fund’s returns by reducing the fund’s exposure to the equity and/or currency markets as represented by the underlying funds and also to potentially expose the fund to asset classes and/or markets in which the underlying funds have little or no exposure (e.g., high income debt instruments). In addition, MFS may use derivatives to seek to limit the fund’s exposure to certain extreme market events.

Derivatives include futures, forward contracts, options, and swaps.

It is expected that the fund will generally have lower volatility than that of the overall equity market.

The portfolio managers are responsible for selecting the underlying funds, determining the target strategic allocations to the underlying funds, and determining the fund's tactical allocation overlay.

Strategic Fund Allocation: The underlying funds are selected by the portfolio managers based on underlying fund classifications, historical risk, performance, and other factors. MFS expects the fund’s target allocation to be equally weighted among the following underlying funds: MFS Growth Fund, MFS International Equity Fund, and MFS Value Fund.

A portion of the fund's assets (approximately 10%-15%) will typically be held in cash, cash equivalents, and/or short-term government securities due to collateral requirements for the fund's investments in derivatives, purchase and redemption activity, and other short term cash needs.

Tactical Asset Allocation Overlay: MFS implements the tactical asset allocation overlay primarily through the use of derivative instruments based on the portfolio managers' assessment of the relative attractiveness of asset classes and markets. In seeking to reduce the fund's volatility, MFS decreases the fund’s exposure to the equity and/or currency markets represented by the underlying funds. In addition, MFS may expose the fund to asset classes and/or markets in which the underlying funds have little or no exposure (e.g., high income debt instruments or small cap equity securities) when the portfolio managers believe such asset classes or markets are relatively attractive.

After taking into account the tactical asset allocation overlay, the fund's total market exposure will normally be between 10% and 90% of the fund's assets. (The fund's total market exposure includes the fund's exposure to the equity market through investment in the underlying funds and exposure to any other markets through the tactical overlay.) When the portfolio managers' assessment of the relative attractiveness of asset classes and markets is neutral, the fund's exposure to the equity market is expected to be approximately 50% of the fund's assets.

After taking into account the tactical overlay, the fund may have significant exposure to issuers in a single sector, industry, country, or region.

MFS' tactical asset allocation process for the fund will typically make extensive use of derivatives.

In light of the fund’s principal investment strategies described above, MFS believes it is reasonable to measure the fund’s performance (net of fund expenses) over a full market cycle relative to the performance of (i) the ICE BofA 0-3 Month U.S. Treasury Bill Index plus 2% to 4% and (ii) the Standard & Poor's 500 Stock Index. MFS does not seek to achieve a specific rate of return in managing the fund and there is no assurance that the fund will outperform the ICE BofA 0-3 Month U.S. Treasury Bill Index or the Standard & Poor's 500 Stock Index over the long term or for any year or period of years.

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 corresponds to the fund's principal investment strategies.

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 mfs.com or by calling 1-800-225-2606.

The total return for the six-month period ended June 30, 2026, was 1.35%. During the period(s) shown in the bar chart, the highest quarterly return was 4.13% (for the calendar quarter ended March 31, 2024) and the lowest quarterly return was (3.28)% (for the calendar quarter ended March 31, 2022).

Investment Strategy Risk: The fund’s strategy to reduce its exposure to the equity and/or currency markets represented by the underlying funds and to potentially expose the fund to asset classes and/or markets in which the underlying funds have little or no exposure may not produce the intended results. There is no assurance that the fund will be less volatile than the overall equity

market over the long term or for any year or period of years. In addition, the strategies MFS may implement to limit the fund’s exposure to certain extreme market events may not work as intended, and the costs associated with such strategies will reduce the fund’s returns. It is expected that the fund will generally underperform the equity markets during periods of strong, rising equity markets.

Underlying Funds Risk: MFS' strategy of investing in underlying funds exposes the fund to the risks of the underlying funds. Each underlying fund pursues its own investment objective and strategies and may not achieve its objective. In addition to the fees and expenses the fund bears directly, shareholders of the fund will indirectly bear the fees and expenses of the underlying funds.

Equity Market Risk/Company Risk: Equity markets are 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 issuer or type of security, issuers within a broad market sector, industry or geographic region, or the equity markets in general. Certain events can have a dramatic adverse effect on equity markets and may lead to periods of high volatility in an equity market or a segment of an equity market. The value of an investment held by the fund may decline due to factors directly related to the issuer.

Emerging Markets Risk: Investments tied economically to emerging markets, especially frontier markets, can involve additional and greater risks than the risks associated with investments in developed markets. Emerging markets can have less developed markets, greater custody and operational risk, less developed legal, regulatory, and accounting systems, greater government involvement in the economy, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater political, social, geopolitical, and economic instability than developed markets.

Focus Risk: Issuers in a single industry, sector, 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 industries, sectors, countries, and regions to which the fund is exposed. Furthermore, investments in particular industries, sectors, countries, or regions may be more volatile than the broader market as a whole.

Value Company Risk: The stocks of value companies can continue to be undervalued for long periods of time and not realize their expected value and can be more volatile than the market in general.

Debt Market Risk: 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.

Credit Risk: 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.

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.

Counterparty and Third Party Risk: 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.

Large Shareholder 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 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.