Strategy. The Portfolio is managed by AllianceBernstein L.P. (AllianceBernstein) under a sub-advisory agreement with the Adviser. The Portfolio invests primarily in a diversified portfolio of equity securities with relatively smaller capitalizations as compared to the overall U.S. market. Under normal circumstances, the Portfolio invests at least 80% of its net assets in the equity securities of mid- capitalization companies with public stock market capitalization (based upon shares available for trading on an unrestricted basis) within the range of the market capitalization of companies constituting the Russell Midcap Index at the time of investment. As of March 31, 2025 the capitalization range of the Russell Midcap Index was between $272.6 million and $189.81 billion. Because the Portfolios definition of mid-capitalization companies is … Show more… The Portfolio is managed by AllianceBernstein L.P. (AllianceBernstein) under a sub-advisory agreement with the Adviser. The Portfolio invests primarily in a diversified portfolio of equity securities with relatively smaller capitalizations as compared to the overall U.S. market. Under normal circumstances, the Portfolio invests at least 80% of its net assets in the equity securities of mid- capitalization companies with public stock market capitalization (based upon shares available for trading on an unrestricted basis) within the range of the market capitalization of companies constituting the Russell Midcap Index at the time of investment. As of March 31, 2025 the capitalization range of the Russell Midcap Index was between $272.6 million and $189.81 billion. Because the Portfolios definition of mid-capitalization companies is dynamic, the limits on market capitalization will change with the markets. In the future, the Portfolio may define mid-capitalization companies using a different classification system. In managing the Portfolio, AllianceBernstein diversifies between portions, or sleeves, of the Portfolio that utilize active and passive strategies. The Portfolio targets a strategic allocation of 50% of the Portfolios net assets to an actively managed sleeve, with the remaining 50% managed in a passive strategy that seeks to track the performance of the Russell Midcap Index, an unmanaged securities index, although the allocation may range between 35% - 65%, with the objective of achieving a style balanced portfolio with attractive risk adjusted returns relative to its benchmark, the Russell Midcap Index, over full market cycles. The active and passive sleeves are rebalanced back to target weights should they exceed pre-defined thresholds. Active Sleeve: The Portfolios active sleeve is comprised of two components, a US Mid-Cap Growth strategy and a US Mid-Cap Value strategy that are periodically rebalanced back to target weights should they exceed pre-defined thresholds. US Mid-Cap Growth: The Portfolios investment policies emphasize investments in companies that are demonstrating improving financial results and a favorable earnings outlook. The Portfolio may invest in foreign securities. When selecting securities, AllianceBernstein typically looks for companies that have strong, experienced management teams, strong market positions, and the potential to support greater than expected earnings growth rates. In making specific investment decisions for the Portfolio, AllianceBernstein combines fundamental and quantitative analysis in its stock selection process. The Portfolio may periodically invest in the securities of companies that are expected to appreciate due to a development particularly or uniquely applicable to that company regardless of general business conditions or movements of the market as a whole. US Mid-Cap Value: The Portfolio invests in companies that are determined by AllianceBernstein to be undervalued, using AllianceBernsteins fundamental value approach. In selecting securities for the Portfolios portfolio, AllianceBernstein uses its fundamental and quantitative research to identify companies whose long-term earnings power is not reflected in the current market price of their securities. In selecting securities for the Portfolio, AllianceBernstein looks for companies with attractive valuation (for example, with attractive price to free cash flow ratios) and compelling success factors (for example capital discipline and return on equity). AllianceBernstein uses this information to calculate an expected return and ranking. The rankings are used to determine prospective candidates for possible addition to the portfolio. Typically, AllianceBernstein focuses its research on the most attractive 40% of the universe. AllianceBernstein typically projects a companys financial performance over a full economic cycle, including a trough and a peak, within the context of forecasts for real economic growth, inflation and interest rate changes. AllianceBernstein focuses on the valuation implied by the current price, relative to the earnings the company will be generating five years from now, or normalized earnings, assuming average mid-economic cycle growth for the fifth year. Generally, a security is sold when it no longer meets appropriate valuation criteria, although sales may be delayed when positive return trends are favorable. Typically, growth in the size of a companys market capitalization relative to other domestically traded companies will not cause the Portfolio to dispose of the security. AllianceBernstein seeks to manage overall portfolio volatility relative to the universe of companies that comprise the lowest 20% of the total U.S. market capitalization by favoring promising securities that offer the best balance between return and targeted risk. At times, the Portfolio may favor or disfavor a particular sector compared to that universe of companies. The Portfolio may invest significantly in companies involved in certain sectors that constitute a material portion of the universe of small- and mid- capitalization companies. Passive Sleeve: The Portfolios passive component seeks to track the Russell Midcap Index (the Index) using a representative sampling of Index constituents, and rebalances annually on the same schedule as the Index, as well as quarterly to add eligible IPOs, also on the same schedule as the Index. The Index seeks to measure the mid-cap segment of the US equity market and employs a free-float adjusted market capitalization-weighted approach. Derivatives The Portfolio invests principally in equity securities but may also invest in other types of securities, such as preferred stocks. The Portfolio, at times, invests in shares of exchange-traded funds (ETFs) in lieu of making direct investments in securities. ETFs may provide more efficient and economical exposure to the types of companies and geographic locations in which the Portfolio seeks to invest than direct investments. The Portfolio may also invest up to 20% of its total assets in rights and warrants, which are instruments that entitle the holder to purchase an equity security at a specific price for a specific period of time. The Portfolio may enter into derivatives transactions, such as options, futures contracts, forwards and swaps to manage risk and to seek to generate additional returns. The Portfolio may use options strategies involving the purchase and/or writing of various combinations of call and/or put options, including on individual securities and stock indices, futures contracts (including futures contracts on individual securities and stock indices) or shares of ETFs. These transactions may be used, for example, in an effort to earn extra income, to adjust exposure to individual securities or markets, or to protect all or a portion of the Portfolios portfolio from a decline in value, sometimes within certain ranges. Show less