The investment seeks to track the investment results (before fees and expenses) of the CBOE S&P 500 BuyWrite IndexSM. The fund generally will invest at least 90% of its total assets in the securities that comprise the underlying index and will write (sell) call options thereon. The underlying index is a total return benchmark index that is designed to track the performance of a hypothetical buy-write strategy on the S&P 500® Index.