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 Defined Mid Cap Core Index. The fund will normally invest at least 90% of its net assets in common stocks that comprise the index. The index is a modified equal-dollar weighted index designed by S&P to objectively identify and select stocks from the S&P MidCap 400(R) Index that may generate positive alpha relative to traditional passive-style indices through the use of the AlphaDEX(R) selection methodology. It is non-diversified.