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

In the year to Sep 12, 2026, with distributions reinvested, IWM returned +21.2% and MBB returned −0.1%, so IWM returned more. One year is one year; the longer windows are in the table.

Which is cheaper, IWM or MBB?

IWM charges 0.19% a year and MBB charges 0.04%, so MBB is cheaper. Fees come from each fund's prospectus.

Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.

ETFIQetfiq.com · independent ETF data

IWM vs MBB: how they differ

IWM and MBB hold 0% of their weight in the same names, and IWM returned more over the year.

iShares Russell 2000 ETF and iShares MBS ETF.

What they hold in common

By the books each fund has filed, IWM and MBB hold 0% of their money in the same securities at the same weight.

Largest positions each one holds and the other does not
Only in IWM	Only in MBB
Moog, Inc. 0.38%	Freddie Mac 1.07%
Hut 8 Corp. 0.37%	Government National Mortgage Association 0.97%
Viasat, Inc. 0.35%	UMBS, TBA 0.85%
BrightSpring Health Services, Inc. 0.35%	Government National Mortgage Association 0.69%
Cytokinetics, Inc. 0.35%	UMBS, TBA 0.66%
MaxLinear, Inc. 0.34%	Government National Mortgage Association 0.56%
Argan, Inc. 0.34%	Government National Mortgage Association 0.55%
UMB Financial Corp. 0.33%	Government National Mortgage Association 0.54%

Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed. Above 50%, holding both is close to holding one of them twice. Holdings dated Jun 30, 2026 and May 31, 2026.

IWM and MBB on the fields both publish, as of Sep 12, 2026. Source: ETFIQ.
	IWM iShares Russell 2000 ETF	MBB iShares MBS ETF
Where it sits	Core index fund	Core index fund
Issuer	iShares	iShares
What it is	Russell 2000	Mbs
Total return, 1 year	+21.2%	−0.1%
S&P 500 over the same days	+17.5%	+17.5%
Gap to the S&P 500	+3.7 pts	−17.6 pts
Expense ratio	0.19%	0.04%
Holdings	2014	11144

IWM in plain words

IWM is an index equity fund tracking the Russell 2000. Over the year to Sep 11, 2026 it returned +21.2% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.19% a year. By its holdings filed for Jun 30, 2026, 0% of the fund by weight is stocks the S&P 500 also holds, across 2014 positions, with the top ten at 3.4%. It sat 5.3% below its high of Aug 14, 2026 on Sep 11, 2026.

MBB in plain words

MBB is a bond fund tracking the Mbs. Over the year to Sep 11, 2026 it returned −0.1% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.04% a year. It sat 3.3% below its high of Feb 27, 2026 on Sep 11, 2026.

Questions people ask

Which returned more over the last year, IWM or MBB?: In the year to Sep 12, 2026, with distributions reinvested, IWM returned +21.2% and MBB returned −0.1%, so IWM returned more. One year is one year; the longer windows are in the table.
Which is cheaper, IWM or MBB?: IWM charges 0.19% a year and MBB charges 0.04%, so MBB is cheaper. Fees come from each fund's prospectus.

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Where these figures came from

ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.

IWM against MBB, ETFIQ, data as of Sep 12, 2026. Every figure is arithmetic on a named public source; the method is at etfiq.com/methodology. A comparison is not a recommendation.

Cite this page. ETFIQ, IWM against MBB, data as of Sep 12, 2026. https://etfiq.com/compare/any/IWM-MBB Free to use with attribution; the underlying files are at Open data.

A comparison is not a recommendation. Standards and sources