Vanguard Bond Index Funds (the Fund), formerly Vanguard Long-Term Bond ETF, seeks to track the performance of a market-weighted bond index with a long-term, dollar-weighted average maturity. It employs a passive management or indexing strategy designed to track the performance of the Barclays Capital U.S.Long Government/Credit Bond Index (the Index). The Index includes all medium and larger issues of the United States Government, investment-grade corporate, and investment-grade international dollar-denominated bonds that have maturities of greater than 10 years and are publicly issued. The Fund invests by sampling the Index, meaning that it holds a range of securities that, in the aggregate, approximates the full Index in terms of key risk factors and other characteristics. All of the Fund�s investments will be selected through the sampling process, and at least 80% of its assets will be invested in bonds held in the Index. The Fund�s investment advisor is The Vanguard Group, Inc.