The PowerShares Water Resources Portfolio (Fund) is based on the NASDAQ OMX US Water Index. The Fund generally will invest at least 90% of its total assets in common stocks and American depositary receipts (ADRs) of companies in the water industry that comprise the Underlying Index. The Underlying Index seeks to track the performance of US exchange-listed companies that create products designed to conserve and purify water for homes, businesses and industries. The Fund and the Index are rebalanced quarterly and reconstituted annually in April.