Strategy. MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the funds 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 Growth Index over the last 13 months at the time of purchase. As of March 31, 2025, the range of the market capitalizations of the issuers in the Russell Midcap Growth Index was between approximately $681.0 million and $198.0 billion. MFS normally invests the funds assets primarily in equity securities. Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in … Show more… MFS (Massachusetts Financial Services Company, the fund's investment adviser) normally invests at least 80% of the funds 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 Growth Index over the last 13 months at the time of purchase. As of March 31, 2025, the range of the market capitalizations of the issuers in the Russell Midcap Growth Index was between approximately $681.0 million and $198.0 billion. MFS normally invests the funds assets primarily in equity securities. Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer. MFS focuses on investing the funds assets in the stocks of companies it believes have above average potential with respect to the rate and duration of earnings growth compared to other companies (growth companies). MFS may invest the funds 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. Show less