Generated August 16, 2026.
Overview
AGG and BND are nearly identical broad-market U.S. bond ETFs tracking slightly different versions of the Bloomberg Aggregate Bond Index—AGG follows the standard index, while BND tracks the float-adjusted variant. Both offer monthly income, charge 0.03% in expenses, and hold the same core mix of Treasuries, investment-grade corporates, and mortgage-backed securities. The meaningful differences lie in index construction, fund size, and inception timing rather than strategy or cost.
How they differ
The biggest structural difference is their underlying indexes: AGG uses the Bloomberg U.S. Aggregate Bond Index (which includes all outstanding bonds), while BND uses the Bloomberg U.S. Aggregate Float Adjusted Index (which weights bonds by their available supply in the market). This typically results in BND holding slightly fewer issues but with similar sector and duration exposure. Their yields are nearly identical at 4.16% and 4.17%, respectively, and both distribute monthly. BND has a larger asset base at $162B versus AGG's $138B, which can translate to slightly tighter bid-ask spreads for BND, though both are highly liquid. The expense ratios are identical at 0.03%, so cost is a wash.
Who each is best for
AGG: Fits investors seeking the purest version of the full U.S. bond market, including every security the Bloomberg index captures, with a longer track record dating to 2003 for those valuing historical consistency.
BND: Designed for investors who prefer market-cap-weighted exposure based on what's actually tradeable in the market, plus the marginal benefit of a larger fund with slightly deeper liquidity and Vanguard's ownership structure.
Key risks to know
- Duration and rate risk: Both ETFs are sensitive to interest rate moves at roughly the same degree (beta near 1.0), so rising rates will pressure NAV similarly across both funds.
- Credit spread widening: Economic weakness could widen spreads on the corporate and securitized portions of both portfolios, though this risk is shared and comparable.
- Index construction divergence: The float-adjustment methodology in BND may cause its holdings to drift from AGG's over time, particularly in illiquid or newly issued bonds, creating modest performance variance despite their similar mandates.
- Reinvestment risk in a declining-rate environment: Monthly distributions paid from coupon income face reinvestment at lower yields if rates fall, though this affects both funds equally.
Bottom line
If you want the broadest possible index universe and value a longer inception date for performance history, AGG delivers that; if you prefer float-adjusted market-cap weighting and slightly larger fund scale, BND fills that role. The practical performance difference between them is likely to be negligible, making either a solid anchor for bond exposure. Past performance does not predict future results.
AI-generated analysis for educational purposes only. Verify important details independently; past performance does not guarantee future results.