The investment seeks investment results that correspond generally to the price and yield (before the fund's fees and expenses) of an equity index called the Nasdaq AlphaDEX® Mid Cap Core Index. The fund will normally invest at least 90% of its net assets (including investment borrowings) in the common stocks that comprise the index. The index is designed to select stocks from the NASDAQ US 600 Mid Cap Index (the base index) that may generate positive alpha, or risk-adjusted returns, relative to traditional indices through the use of the AlphaDEX® selection methodology.