Data as of Oct 28, 2026.
BND vs MBB: Differences, Returns & Fees
BND's duration was 5.7 years on Jun 30, 2026 and MBB's 5.7 on Aug 31, 2026; BND charges 0.03% to MBB's 0.04%.
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Net assets: $161.4bn on Sep 30, 2026 for Vanguard Total Bond Market ETF, and $35.5bn on Oct 28, 2026 for iShares MBS ETF.
Pair scorecard
BND costs 0.01 points a year less; their one-year returns differ by 0.5 points; BND is 4.5 times larger.
| Measure | BND | MBB |
|---|---|---|
| Return | ||
| Total return, 1 year | −1.3% | −0.8% |
| Drawdown | ||
| Below its high | 3.5%, high on Aug 6, 2020 | |
| Benchmark | ||
| What it tracks | Bloomberg U.S. Aggregate Float Adjusted Index | Bloomberg U.S. MBS Index |
| Cost and size | ||
| Expense ratio | 0.03% | 0.04% |
| Net assets, as of Sep 30, 2026 | $161.4bn | $36.2bn |
| Holdings | ||
| Holdings in common | 5% | |
Holdings in common uses holdings dated Jun 30, 2026 and Aug 31, 2026. Method
Risk and return
Apr 20, 2007 to Oct 23, 2026 · 1,018 weekly returnsEach against its own benchmark: BND against AGG, Apr 20, 2007 to Oct 23, 2026; MBB against SPMB, Feb 6, 2009 to Oct 23, 2026.
BND returned more: +75.5% to +63.4%. MBB swung less: 4.2% to 5.0%. MBB fell slightly less at its worst: −17.4% to −18.4%.
Full scorecard
19 measures, with how each is measured Open ↓
| Measure | BND | MBB | Edge | How it is measured |
|---|---|---|---|---|
| Return | ||||
| Total return | +75.5% | +63.4% | BND | Price change plus distributions, reinvested. |
| Annualized | +2.9% | +2.5% | BND | Total return as a yearly rate. |
| Price return | −5.4% | −9.4% | BND | Price change alone, distributions left out. |
| Risk | ||||
| Volatility | 5.0% | 4.2% | MBB | Spread of weekly returns, annualized. Lower is steadier. |
| Downside deviation | 3.7% | 2.9% | MBB | Like volatility, counting only weeks below the Treasury bill rate. |
| Max drawdown | −18.4% | −17.4% | MBB (slight) | Deepest fall from a high to the low after it. |
| Upside capture | 95.8% | 77.8% | Share of its benchmark's rise caught in the weeks it rose. | |
| Downside capture | 95.6% | 78.4% | Share of its benchmark's fall taken in the weeks it fell. Lower is better. | |
| Beta | 0.91 | 0.76 | Not an edge | How far it moves for each 1% its benchmark moves. |
| R squared | 0.94 | 0.76 | Not an edge | Share of its weekly moves its benchmark explains. |
| Risk-adjusted | ||||
| Sharpe | 0.29 | 0.25 | BND | Return above Treasury bills per unit of volatility. |
| Sortino | 0.39 | 0.36 | BND (slight) | Return above Treasury bills per unit of downside deviation. |
| Treynor | 0.016 | 0.009 | Return above Treasury bills per unit of beta. | |
| Calmar | 0.16 | 0.15 | BND (slight) | Annualized return divided by the max drawdown. |
| Against the benchmark | ||||
| Benchmark | AGG | SPMB | The ETF each fund is measured against. | |
| Alpha | +0.2% a year | +0.1% a year | Not significant | Yearly return beyond what its beta to the benchmark predicts. |
| Alpha t-stat | 0.59 | 0.26 | Not an edge | How sure the alpha is. Below 2, it could be chance. |
| Alpha range | −0.4% to +0.7% | −0.8% to +1.1% | Includes zero | The 95% range for the yearly alpha. |
| Information ratio | 0.03 | −0.03 | Return against its benchmark per unit of tracking error. | |
| Tracking error | 1.3% | 2.3% | Not an edge | How far weekly returns stray from the benchmark, annualized. |
Computed by ETFIQ from Tiingo daily prices and ETFIQ's distribution records, 1,018 weekly returns. Cash rate: the 13-week Treasury bill.
What they share
By the books each fund has filed, BND and MBB hold 5% of their money in the same securities at the same weight. Holdings dated Jun 30, 2026 and Aug 31, 2026.
half
5% in common
Only in one fund ↓
Side by side
BND and MBB on the fields both publish, as of Oct 28, 2026. Source: ETFIQ.
BND and MBB do different jobs. What does each one do in a portfolio?
- What each follows. BND follows Bloomberg U.S. Aggregate Float Adjusted Index and MBB follows Bloomberg U.S. MBS Index.
- Holdings in common. 5% of the weight is in the same securities (holdings dated Jun 30, 2026 and Aug 31, 2026).
- Size. BND has $161.4bn in net assets and MBB $36.2bn (net assets, as of Sep 30, 2026); BND is 4.5 times larger.
Data as of Oct 28, 2026.
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BND
BND tracks an index of US aggregate bonds. Over the year to Oct 28, 2026 it returned −1.3% with distributions reinvested, against −1.4% for its benchmark, the Bloomberg U.S. Aggregate Float Adjusted Index, measured by the closely related Bloomberg U.S. Aggregate Bond Index. The prospectus expense ratio is 0.03% a year. It sat 3.5% below its high of Aug 6, 2020 on Oct 28, 2026.
MBB
MBB tracks an index of mortgage-backed securities. Over the year to Oct 28, 2026 it returned −0.8% with distributions reinvested, against −1.1% for its benchmark, the Bloomberg U.S. MBS Index. The prospectus expense ratio is 0.04% a year.
Questions people ask
- Which returned more over the last year, BND or MBB?
- In the year to Oct 28, 2026, with distributions reinvested, BND returned −1.3% and MBB −0.8%.
- Which is cheaper, BND or MBB?
- BND is cheaper, by 0.01 percentage points a year. That is about $1 on $10,000 held for a year. Fees come from each fund's prospectus.
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How this is computed
Overlap adds up the smaller of the two weights for each security both funds hold.
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ETFIQ, BND against MBB, data as of Oct 28, 2026. https://etfiq.com/compare/any/bnd-vs-mbb
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