iShares Barclays 20+ Year Treasury Bond Fund (the Fund), formerly iShares Lehman 20+ Year Treasury Bond Fund, seeks investment results that correspond generally to the price and yield performance of the long-term sector of the United States Treasury market as defined by the Barclays Capital U.S. 20+ Year Treasury Bond Index (the Index). The Index is a market capitalization-weighted index. The Index includes all publicly issued, the United States Treasury securities that have a remaining maturity greater than 20 years, are non-convertible, are denominated in United States dollars, are rated investment grade (Baa3 or better) by Moody’s Investors Service, are fixed rate and have more than $150 million par outstanding. The Fund invests in a representative sample of securities included in the Index that collectively has an investment profile similar to the Index. The Fund’s investment advisor is Barclays Global Fund Advisors.