The PowerShares Insured National Municipal Bond Portfolio (Fund) is based on The BofA Merrill Lynch National Insured Long-Term Core Plus Municipal Securities Index (Index). The Fund will normally invest at least 80% of its total assets in securities that comprise the Index and generally expects to invest at least 90% of its total assets. The Index is designed to track the performance of US dollar-denominated, investment grade, insured tax-exempt debt publicly issued by US municipalities in the US domestic market. The Index is adjusted monthly and its constituents are capitalization-weighted based on their current amount outstanding. The Fund and the Index are rebalanced and reconstituted monthly.