The fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities, consisting of common stocks, preferred stocks, convertible securities, warrants, and rights of “mid-cap discovery companies.” In addition to the fund's investments in domestic securities, it may invest up to 20% of its net assets in sponsored or unsponsored ADRs and securities of foreign companies that are traded on U.S. stock exchanges.