Vanguard Total Bond Market Index Fund is an exchange-traded fund that provides broad exposure to the U.S. investment-grade bond market. The fund seeks to track the performance of the Bloomberg U.S. Aggregate Float Adjusted Index, which includes U.S. Treasuries, government-related and corporate bonds, as well as agency mortgage-backed and asset-backed securities. It focuses on U.S. dollar-denominated, fixed-rate, taxable bonds and excludes inflation-protected and tax-exempt securities. The portfolio is intermediate in duration and emphasizes high credit quality, aiming to deliver moderate current income with relatively lower credit risk compared with high-yield segments. Using a passive, index-sampling approach, Vanguard Total Bond Market Index Fund is commonly used as a core fixed income holding, providing diversified exposure across sectors, maturities, and issuers within the U.S. bond market. The fund is managed by Vanguard, headquartered in Malvern, Pennsylvania.