Strategy. Principal Investment Strategies The Fund invests primarily in domestic equity securities that the Funds subadvisers believe offer the potential for long-term growth. The Fund is managed by two subadvisers, Wellington Management Company LLP (Wellington Management) and Westfield Capital Management Company, L.P. (Westfield), each being responsible for a portion of the portfolio, although they may manage different amounts of the Funds assets. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stock, rights, and warrants. While the Fund may invest in issuers of any size, the Fund currently focuses on securities of mid-capitalization companies. While most assets will be invested in equity securities of U.S. companies, the Fund may also invest up to 20% of its … Show more… Principal Investment Strategies The Fund invests primarily in domestic equity securities that the Funds subadvisers believe offer the potential for long-term growth. The Fund is managed by two subadvisers, Wellington Management Company LLP (Wellington Management) and Westfield Capital Management Company, L.P. (Westfield), each being responsible for a portion of the portfolio, although they may manage different amounts of the Funds assets. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stock, rights, and warrants. While the Fund may invest in issuers of any size, the Fund currently focuses on securities of mid-capitalization companies. While most assets will be invested in equity securities of U.S. companies, the Fund may also invest up to 20% of its total assets in foreign securities and American Depositary Receipts (ADRs), including emerging market securities. The Fund may at times have significant exposure to one or more industries or sectors. The Fund may hold a portion of its assets in cash or cash equivalents. Wellington Management seeks to outperform the Russell Midcap Growth Index over full market cycles by investing in secular growth companies with high returns on invested capital that are attractively priced relative to their long-term earnings power. Key stock selection criteria include long-term earnings power, forecasted return on invested capital, valuation, and quantitative risk factors. Portfolio weights are selected using a risk-based approach. The portfolio management process seeks to minimize sector risk as sector allocation is a fallout of the bottom-up security selection process. Wellington Management will generally sell a security if one or more of the following occurs: the stock price rises to a point where the risk/reward outlook for the company is no longer considered attractive; company fundamentals deteriorate or the investment thesis changes; more attractive investment candidates are identified; or market capitalization exceeds guidelines. Westfield invests primarily in stocks of domestic growth companies that it believes have a demonstrated record of achievement with excellent prospects for earnings growth over a 1 to 3 year period. In choosing securities, Westfield looks for companies that it believes are reasonably priced with high forecasted earnings potential. Westfield generally will sell a security if one or more of the following occurs: Westfields predetermined price target objective is exceeded; there is an alteration to the original investment case; valuation relative to the stocks peer group is no longer attractive; or better risk/reward opportunities may be found in other stocks. The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate. Show less