The investment seeks long-term capital appreciation. The fund normally invests at least 80% of its net assets in equity securities issued by U.S. mid-capitalization companies which the fund management believes have above-average earnings growth potential. The fund adviser generally defines these companies, at the time of the fund's investment, as those with market capitalizations comparable in size to the companies in the Russell Midcap® Growth Index. It primarily invests in common stock but also can invest in preferred stock, convertible securities and other equity securities.