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Data as of Oct 28, 2026.

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GOVT vs MBB: Differences, Returns & Fees

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GOVT's duration was 5.5 years on Jul 31, 2026 and MBB's 5.7 on Aug 31, 2026; MBB charges 0.04% to GOVT's 0.05%.

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Net assets: $42.8bn on Oct 27, 2026 for iShares U.S. Treasury Bond ETF, and $35.5bn on Oct 28, 2026 for iShares MBS ETF.

GOVT on its own →MBB on its own →
At a glance
−1.5%
GOVT total return, 1 year
−0.8%
MBB total return, 1 year
0.05%
GOVT expense ratio
0.04%
MBB expense ratio

Pair scorecard

MBB costs 0.01 points a year less; their one-year returns differ by 0.7 points; GOVT is 1.2 times larger.

GOVT vs MBB: Differences, Returns & Fees
MeasureGOVTMBB
Return
Total return, 1 year−1.5%−0.8%
Drawdown
Below its high8.1%, high on Aug 4, 2020
Benchmark
What it tracksICE U.S. Treasury Core Bond IndexBloomberg U.S. MBS Index
Cost and size
Expense ratio0.05%0.04%
Net assets, as of Oct 26, 2026$42.8bn$35.6bn
Holdings
Holdings in common0%

Holdings in common uses holdings dated Jul 31, 2026 and Aug 31, 2026. Method

What they share

0%

By the books each fund has filed, GOVT and MBB hold 0% of their money in the same securities at the same weight. Holdings dated Jul 31, 2026 and Aug 31, 2026.

0 half 100%

half

0% in common

Positions both hold · largest shared weight first GOVT MBB
Only in one fund ↓
Only in GOVT
U.S. Treasury Notes, due Nov 15, 2031 5.28%
U.S. Treasury Notes, due Feb 15, 2029 2.95%
U.S. Treasury Notes, due Feb 15, 2028 2.63%
U.S. Treasury Notes, due Nov 15, 2028 2.08%
U.S. Treasury Notes, due May 15, 2028 1.62%
U.S. Treasury Bonds, due May 15, 2046 1.48%
U.S. Treasury Bonds, due Nov 15, 2042 1.46%
U.S. Treasury Bonds, due Feb 15, 2051 1.46%
Only in MBB
Ginnie Mae, due Sep 1, 2056 1.05%
Freddie Mac Pool, due May 1, 2051 0.98%
Uniform Mortgage-Backed Security, TBA, due Sep 1, 2056 0.85%
Uniform Mortgage-Backed Security, TBA, due Sep 1, 2056 0.70%
Ginnie Mae, due Sep 1, 2056 0.53%
Ginnie Mae II Pool, due Nov 20, 2054 0.51%
Ginnie Mae II Pool, due Oct 20, 2051 0.51%
Ginnie Mae II Pool, due Dec 20, 2051 0.50%
Check overlap with more funds →

Side by side

GOVT iShares U.S. Treasury Bond ETF MBB iShares MBS ETF
Where it sits Bond ETF Bond ETF
Issuer iShares iShares
What it is Tracks an index of U.S. Treasury Bond Tracks an index of mortgage-backed securities
Total return, 1 year −1.5% −0.8%
Its benchmark over the same days not measured −1.1% (SPMB)
Gap to its benchmark not measured +0.3 pts vs SPMB
Expense ratio 0.05% 0.04%
Holdings 229 10813
Net assets, GOVT as of Oct 27, 2026 and MBB as of Oct 28, 2026 $42.8bn $35.5bn

GOVT and MBB on the fields both publish, as of Oct 28, 2026. Source: ETFIQ.

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About each fund
GOVT

GOVT tracks an index of U.S. Treasury Bond. Over the year to Oct 28, 2026 it returned −1.5% with distributions reinvested. The prospectus expense ratio is 0.05% a year. It sat 8.1% below its high of Aug 4, 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, GOVT or MBB?
In the year to Oct 28, 2026, with distributions reinvested, GOVT returned −1.5% and MBB −0.8%.
Which is cheaper, GOVT or MBB?
MBB 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.
Other comparisons
GOVT vs PULSGOVT vs USFRGOVT vs IEIGOVT vs SCHPIEF vs MBBMBB vs VGITMBB vs VGSHMBB vs VCIT
Where to next
GOVT on its own →MBB on its own →Hold both: look the portfolio through →Rankings →GOVT dividend history →GOVT holdings →MBB dividend history →MBB holdings →Standards and sources →
Sources and dates
GOVT and MBB filings on SEC EDGAR ↗
GOVT prospectus with the expense ratio (SEC) ↗
iShares page for GOVT ↗
MBB prospectus with the expense ratio (SEC) ↗
iShares page for MBB ↗

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, GOVT against MBB, data as of Oct 28, 2026. https://etfiq.com/compare/any/govt-vs-mbb

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Free to use with attribution for data ETFIQ computes; issuer data stays under its owner's terms.