The investment seeks investment results that generally correspond (before fees and expenses) to the price and yield of the Wells Fargo® Hybrid and Preferred Securities Floating and Variable Rate Index. The index is a market capitalization-weighted index designed to track the performance of preferred stock, as well as certain types of "hybrid securities" that are functionally equivalent to preferred stocks, that are issued by US-based or foreign issuers and that pay a floating or variable rate dividend or coupon. The fund generally will invest at least 90% of its total assets in the securities that comprise the index. It is non-diversified.