Data as of Oct 28, 2026.
MBB vs TLT: Differences, Returns & Fees
On Aug 31, 2026 MBB's duration was 5.7 years and TLT's 15.1; MBB charges 0.04% to TLT's 0.15%.
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Net assets: $35.5bn on Oct 28, 2026 for iShares MBS ETF, and $47.4bn on Oct 27, 2026 for iShares 20+ Year Treasury Bond ETF.
Pair scorecard
MBB costs 0.11 points a year less; their one-year returns differ by 7.1 points; TLT is 1.3 times larger.
| Measure | MBB | TLT |
|---|---|---|
| Return | ||
| Total return, 1 year | −0.8% | −7.9% |
| Drawdown | ||
| Below its high | 42.6%, high on Aug 4, 2020 | |
| Benchmark | ||
| What it tracks | Bloomberg U.S. MBS Index | ICE U.S. Treasury 20+ Year Bond Index |
| Cost and size | ||
| Expense ratio | 0.04% | 0.15% |
| Net assets, as of Oct 26, 2026 | $35.6bn | $47.8bn |
| Holdings | ||
| Holdings in common | 0% | |
Holdings in common uses holdings dated Aug 31, 2026. Method
Risk and return
Mar 23, 2007 to Oct 23, 2026 · 1,022 weekly returnsEach against its own benchmark: MBB against SPMB, Feb 6, 2009 to Oct 23, 2026; TLT against BBLB, Apr 28, 2023 to Oct 23, 2026.
TLT returned slightly more: +69.5% to +63.4%. MBB swung less: 4.2% to 14.2%. MBB fell less at its worst: −17.4% to −47.8%.
Full scorecard
19 measures, with how each is measured Open ↓
| Measure | MBB | TLT | Edge | How it is measured |
|---|---|---|---|---|
| Return | ||||
| Total return | +63.4% | +69.5% | TLT (slight) | Price change plus distributions, reinvested. |
| Annualized | +2.5% | +2.7% | TLT (slight) | Total return as a yearly rate. |
| Price return | −9.6% | −8.4% | TLT | Price change alone, distributions left out. |
| Risk | ||||
| Volatility | 4.2% | 14.2% | MBB | Spread of weekly returns, annualized. Lower is steadier. |
| Downside deviation | 2.9% | 10.0% | MBB | Like volatility, counting only weeks below the Treasury bill rate. |
| Max drawdown | −17.4% | −47.8% | MBB | Deepest fall from a high to the low after it. |
| Upside capture | 77.8% | 102.4% | Share of its benchmark's rise caught in the weeks it rose. | |
| Downside capture | 78.4% | 101.2% | Share of its benchmark's fall taken in the weeks it fell. Lower is better. | |
| Beta | 0.76 | 1.01 | Not an edge | How far it moves for each 1% its benchmark moves. |
| R squared | 0.76 | 1.00 | Not an edge | Share of its weekly moves its benchmark explains. |
| Risk-adjusted | ||||
| Sharpe | 0.24 | 0.15 | MBB | Return above Treasury bills per unit of volatility. |
| Sortino | 0.35 | 0.21 | MBB | Return above Treasury bills per unit of downside deviation. |
| Treynor | 0.009 | −0.072 | Return above Treasury bills per unit of beta. | |
| Calmar | 0.15 | 0.06 | MBB | Annualized return divided by the max drawdown. |
| Against the benchmark | ||||
| Benchmark | SPMB | BBLB | The ETF each fund is measured against. | |
| Alpha | +0.1% a year | 0.0% a year | Not significant | Yearly return beyond what its beta to the benchmark predicts. |
| Alpha t-stat | 0.26 | −0.01 | Not an edge | How sure the alpha is. Below 2, it could be chance. |
| Alpha range | −0.8% to +1.1% | −0.8% to +0.8% | Includes zero | The 95% range for the yearly alpha. |
| Information ratio | −0.03 | −0.10 | Return against its benchmark per unit of tracking error. | |
| Tracking error | 2.3% | 0.7% | Not an edge | How far weekly returns stray from the benchmark, annualized. |
Computed by ETFIQ from Tiingo daily prices and ETFIQ's distribution records, 1,022 weekly returns. Cash rate: the 13-week Treasury bill.
What they share
By the books each fund has filed, MBB and TLT hold 0% of their money in the same securities at the same weight. Holdings dated Aug 31, 2026.
half
0% in common
Only in one fund ↓
Side by side
MBB and TLT on the fields both publish, as of Oct 28, 2026. Source: ETFIQ.
MBB and TLT do different jobs. What does each one do in a portfolio?
- What each follows. MBB follows Bloomberg U.S. MBS Index and TLT follows ICE U.S. Treasury 20+ Year Bond Index.
- Holdings in common. 0% of the weight is in the same securities (holdings dated Aug 31, 2026).
- One-year total return. Over 1 year to Oct 28, 2026 MBB returned −0.8% and TLT −7.9% with distributions reinvested, a gap of 7.1 points.
Data as of Oct 28, 2026.
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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.
TLT
TLT tracks an index of 20+ year Treasuries. Over the year to Oct 28, 2026 it returned −7.9% with distributions reinvested, against −7.8% for its benchmark, the ICE U.S. Treasury 20+ Year Bond Index. The prospectus expense ratio is 0.15% a year. It sat 42.6% below its high of Aug 4, 2020 on Oct 28, 2026.
Questions people ask
- Which returned more over the last year, MBB or TLT?
- In the year to Oct 28, 2026, with distributions reinvested, MBB returned −0.8% and TLT −7.9%.
- Which is cheaper, MBB or TLT?
- MBB is cheaper, by 0.11 percentage points a year. That is about $11 on $10,000 held for a year. Fees come from each fund's prospectus.
Links are sources, not endorsements. A comparison is not a recommendation.
How this is computed
Overlap adds up the smaller of the two weights for each security both funds hold.
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ETFIQ, MBB against TLT, data as of Oct 28, 2026. https://etfiq.com/compare/any/mbb-vs-tlt
ETFIQ. (Oct 28, 2026). MBB against TLT. Retrieved from https://etfiq.com/compare/any/mbb-vs-tlt
[MBB against TLT (ETFIQ, Oct 28, 2026)](https://etfiq.com/compare/any/mbb-vs-tlt)
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