The PowerShares S&P 500 BuyWrite Portfolio (Fund) is based on the CBOE S&P 500 BuyWrite IndexTM (Index). The Fund generally will invest at least 90% of its total assets in securities that comprise the Index, including at least 80% of its total assets in common stocks of the 500 companies included in the S&P 500® Index and will write (sell) call options thereon. The Index measures the total rate of return of an S&P 500 covered call strategy. This strategy consists of holding a portfolio indexed to the S&P 500 (Reference Index) and selling a succession of written options, each with an exercise price at or above the prevailing price level of the S&P 500. Dividends paid on the component stocks underlying the S&P 500 and the dollar value of option premiums received from written options are reinvested. The Fund and the Index are rebalanced and reconstituted quarterly.