Which returned more over the last year, BIL or MBB?

In the year to Oct 28, 2026, with distributions reinvested, BIL returned +3.7% and MBB −0.8%.

Which is cheaper, BIL or MBB?

MBB is cheaper, by 0.10 percentage points a year. That is about $10 on $10,000 held for a year. Fees come from each fund's prospectus.

Data as of Oct 28, 2026.

Across categories

BIL vs MBB: Differences, Returns & Fees

Share on X Download as PDF

BIL's duration was 0.2 years on Jun 30, 2026 and MBB's 5.7 on Aug 31, 2026; MBB charges 0.04% to BIL's 0.14%.

askIQ about this page

askIQ about BIL and MBB

Net assets: $48.7bn on Oct 27, 2026 for SPDR Bloomberg 1-3 Month T-Bill ETF, and $35.5bn on Oct 28, 2026 for iShares MBS ETF.

BIL on its own →MBB on its own →

At a glance

+3.7%

BIL total return, 1 year

−0.8%

MBB total return, 1 year

0.14%

BIL expense ratio

0.04%

MBB expense ratio

Pair scorecard

MBB costs 0.10 points a year less; their one-year returns differ by 4.5 points; BIL is 1.4 times larger.

BIL vs MBB: Differences, Returns & Fees
Measure	BIL	MBB
Return
Measure	BIL	MBB
Total return, 1 year	+3.7%	−0.8%
Benchmark
Measure	BIL	MBB
What it tracks	Bloomberg 1-3 Month U.S. Treasury Bill Index	Bloomberg U.S. MBS Index
Cost and size
Measure	BIL	MBB
Expense ratio	0.14%	0.04%
Net assets, as of Oct 26, 2026	$49.8bn	$35.6bn
Holdings
Measure	BIL	MBB
Holdings in common	0%

Holdings in common uses holdings dated Jun 30, 2026 and Aug 31, 2026. Method

What they share

By the books each fund has filed, BIL and MBB hold 0% of their money in the same securities at the same weight. Holdings dated Jun 30, 2026 and Aug 31, 2026.

50%

0 half 100%

half

0% in common

Positions both hold · largest shared weight first BIL MBB

Only in one fund ↓

Only in BIL

U.S. Treasury Bills, due Aug 6, 2026 12.04%

U.S. Treasury Bills, due Sep 3, 2026 9.04%

U.S. Treasury Bills, due Aug 27, 2026 7.22%

U.S. Treasury Bills, due Sep 17, 2026 7.03%

U.S. Treasury Bills, due Sep 10, 2026 6.98%

U.S. Treasury Bills, due Sep 24, 2026 6.97%

U.S. Treasury Bills, due Aug 13, 2026 6.85%

U.S. Treasury Bills, due Aug 20, 2026 6.49%

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

BIL SPDR Bloomberg 1-3 Month T-Bill ETF MBB iShares MBS ETF

Where it sits Bond ETF Bond ETF

Issuer State Street iShares

What it is Tracks an index of 1-3 month T-bills Tracks an index of mortgage-backed securities

Total return, 1 year +3.7% −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 0.14% 0.04%

Holdings 26 10813

Net assets, BIL as of Oct 27, 2026 and MBB as of Oct 28, 2026 $48.7bn $35.5bn

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

Alert

About each fund

BIL

BIL tracks an index of 1-3 month T-bills. Over the year to Oct 28, 2026 it returned +3.7% with distributions reinvested. The prospectus expense ratio is 0.14% a year.

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, BIL or MBB?: In the year to Oct 28, 2026, with distributions reinvested, BIL returned +3.7% and MBB −0.8%.
Which is cheaper, BIL or MBB?: MBB is cheaper, by 0.10 percentage points a year. That is about $10 on $10,000 held for a year. Fees come from each fund's prospectus.

Other comparisons

BIL vs PFF BIL vs VGLT BIL vs BND BIL vs VGSH MBB vs SHV MBB vs PULS MBB vs USFR MBB vs MINT

Where to next

BIL on its own →MBB on its own →Hold both: look the portfolio through →Rankings →BIL dividend history →BIL holdings →MBB dividend history →MBB holdings →Standards and sources →

Sources and dates

BIL filings on SEC EDGAR ↗

BIL prospectus with the expense ratio (SEC) ↗

State Street website ↗

MBB filings on SEC EDGAR ↗

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.

Cite this pageCitation, APA and Markdown

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

Open data →

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