Strategy. Under normal circumstances, the Portfolio invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in the equity securities of mid-capitalization companies. Securities will be selected using a proprietary quantitative model and will consist primarily of equity securities of companies with similar capitalizations of the companies included in the Russell Midcap ? Growth Index. However, the Portfolio may invest in securities outside the Russell Midcap ? Growth Index capitalization range. The model systematically tracks and ranks the characteristics of large- and mid-capitalization growth issuers located in the United States, and is designed to select stocks based on an analysis of a wide range of factors, such as relative value, earnings quality, market sentiment, … Show more… Under normal circumstances, the Portfolio invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in the equity securities of mid-capitalization companies. Securities will be selected using a proprietary quantitative model and will consist primarily of equity securities of companies with similar capitalizations of the companies included in the Russell Midcap ? Growth Index. However, the Portfolio may invest in securities outside the Russell Midcap ? Growth Index capitalization range. The model systematically tracks and ranks the characteristics of large- and mid-capitalization growth issuers located in the United States, and is designed to select stocks based on an analysis of a wide range of factors, such as relative value, earnings quality, market sentiment, and thematic insights. The Portfolio's sub-adviser is BlackRock Investment Management, LLC ("BlackRock" or the "Sub-Adviser"). The growth investment style generally involves investing in stocks of companies that have shown historical and/or expected above-average growth in such financial metrics as revenue, earnings, cash flow and profit margin. The Portfolio primarily seeks to buy common stock and may also invest in preferred stock and convertible securities listed in U.S. equity markets. Equity securities include common stock, preferred stock, securities convertible into common stock and securities or other instruments whose price is linked to the value of common stock. Preferred stock is a class of stock that often pays dividends at a specified rate and has preference over common stock in dividend payments and liquidation of assets. Convertible securities typically pay current income as either interest (debt security convertibles) or dividends (preferred stock), and their value usually reflects both the stream of current income payments and the market value of the underlying common stock. The Portfolio may use derivatives, including futures, to gain equity exposure and to manage cash flows into or out of the Portfolio effectively. Derivatives are financial instruments whose value is derived from another security, a commodity (such as oil or gas), a currency or an index, including but not limited to the Russell Midcap ? Growth Index. Show less