The PowerShares S&P 500 High Beta Portfolio (Fund) is based on the S&P 500 High Beta Index (Index). The Fund will invest at least 90% of its total assets in common stocks that comprise the Index. The Index is compiled, maintained and calculated by Standard & Poor's and consists of the 100 stocks from the S&P 500 Index with the highest sensitivity to market movements, or beta, over the past 12 months. Beta is a measure of relative risk and is the rate of change of a security's price. The Fund and the Index are rebalanced and reconstituted quarterly in February, May, August and November.