Strategy. The Portfolio attempts to achieve its investment goal by investing, under normal circumstances, at least 80% of its net assets in securities of large capitalization companies. For purposes of such policy, the Portfolio will consider large capitalization companies to be those with market capitalizations similar to companies in the Russell 1000 Index. The Portfolio may invest in foreign securities up to 20% of net assets, including securities of issuers located in emerging markets. The subadviser normally invests the Portfolios assets across different industries and sectors, but the subadviser may invest a significant percentage of the Portfolios assets in a single industry or sector. The subadviser focuses on investing the Portfolios assets in the stocks of companies it believes to have … Show more… The Portfolio attempts to achieve its investment goal by investing, under normal circumstances, at least 80% of its net assets in securities of large capitalization companies. For purposes of such policy, the Portfolio will consider large capitalization companies to be those with market capitalizations similar to companies in the Russell 1000 Index. The Portfolio may invest in foreign securities up to 20% of net assets, including securities of issuers located in emerging markets. The subadviser normally invests the Portfolios assets across different industries and sectors, but the subadviser may invest a significant percentage of the Portfolios assets in a single industry or sector. The subadviser focuses on investing the Portfolios assets in the stocks of companies it believes to have above average earnings growth potential compared to other companies (growth companies). Growth companies tend to have stock prices that are high relative to their earnings, dividends, book value, or other financial measures. The subadviser uses an active bottom-up approach to buying and selling investments for the Portfolio. Investments are selected primarily based on blending fundamental and quantitative research. The subadviser uses fundamental analysis of individual issuers and their potential in light of their financial condition and market, economic, political, and regulatory conditions to determine a fundamental rating for an issuer. Factors considered may include analysis of an issuers earnings, cash flows, competitive position, and management ability. The subadviser may also consider environmental, social, and governance (ESG) factors in its fundamental investment analysis where MFS believes such factors could materially impact the economic value of an issuer. ESG factors considered may include, but are not limited to, climate change, resource depletion, an issuers governance structure and practices, data protection and privacy issues, and diversity and labor practices. The subadviser uses quantitative analysis, including quantitative models that systematically evaluate an issuers valuation, price and earnings momentum, earnings quality, and other factors to determine a quantitative rating for an issuer. The subadviser combines the fundamental rating with the quantitative rating to create a blended rating for an issuer. When a fundamental rating is not available, the subadviser treats the issuer as having a neutral fundamental rating. (The subadvisers quantitative research generates ratings on a greater number of issuers than the subadvisers fundamental research.) The subadviser constructs the portfolio using a portfolio optimization process that considers the blended rating, as well as issuer, industry, and sector weightings, market capitalization, volatility, and other factors. The portfolio managers have the discretion to adjust the inputs and parameters used in the optimization process and the Portfolios holdings based on factors such as the desired portfolio characteristics and the portfolio managers qualitative assessment of the optimization results. The goal is to construct an actively managed portfolio with a target predicted tracking error of approximately 2% compared to the Russell 1000 Growth Index (the Index). Tracking error generally measures how the differences between the Portfolios returns and the Indexs returns have varied over a period of time. A lower tracking error means that there is generally less variation between the Portfolios returns compared to an index that represents the Portfolios investment universe. Third party quantitative risk models are used in the portfolio construction process and to measure the predicted tracking error of the Portfolio. For purposes of the Portfolios 80% policy, net assets include the amount of any borrowings for investment purposes. The Portfolio is non-diversified, which means that it may invest its assets in a smaller number of issuers than a diversified portfolio. Show less