MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the fund’s net assets in issuers with medium market capitalizations. MFS generally defines medium market capitalization issuers as issuers with market capitalizations similar to those of issuers included in the Russell Midcap® Value Index over the last 13 months at the time of purchase. As of December 31, 2025, the range of the market capitalizations of the issuers in the Russell Midcap® Value Index was between approximately $1.3 billion and $101.9 billion.

Effective June 10, 2026, the paragraph directly above is restated in its entirety with the following three paragraphs:

MFS (Massachusetts Financial Services Company, the fund’s investment adviser) normally invests at least 80% of the fund’s net assets in value companies with medium market capitalizations.

MFS defines medium market capitalization companies as issuers that (i) have market capitalizations within the capitalization range of the Russell Midcap® Index over the past 12 months based on the current composition of the index and/or are (ii) classified as a medium capitalization company by an independent third party financial data provider. The market capitalization range of companies considered to have medium capitalizations based on the above criteria will change over time depending on market conditions. For illustrative purposes, as of December 31, 2025, the range of the market capitalizations of the issuers in the Russell Midcap® Index was between approximately $1.3 billion and $101.9 billion, and the fund’s average weighted market capitalization as of that date was $24.4 billion.

Value companies are companies that MFS believes are undervalued compared to their perceived worth in the marketplace. MFS considers a number of factors when determining whether a company is undervalued, including whether (i) the issuer is included in an index which is representative of value companies; (ii) the issuer is classified as a value company by an independent third party financial data provider and/or (iii) the issuer exhibits the characteristics of a value company, considering metrics such as such as price-to-book ratio, price-to-earnings ratio, and dividend yield relative to the applicable equity market. Value companies tend to have stock prices that are low relative to their earnings, dividends, assets, or other financial measures.

MFS normally invests the fund’s assets primarily in equity securities. Equity securities include common stocks, depositary receipts, equity interests in real estate investment trusts (REITs), and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer.

Effective June 10, 2026, the sentence directly below is deleted in its entirety:

MFS focuses on investing the fund's assets in the stocks of companies it believes are undervalued compared to their perceived worth (value companies).

MFS may invest the fund’s assets in foreign securities.

MFS normally invests the fund's assets across different industries and sectors, but MFS may invest a significant percentage of the fund's assets in issuers in a single industry or sector.

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 issuers. Quantitative screening tools that systematically evaluate issuers may also be considered.

For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.