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

In the year to Sep 12, 2026, with distributions reinvested, MBB returned −0.1% and MDY returned +13.0%, so MDY returned more. One year is one year; the longer windows are in the table.

Which is cheaper, MBB or MDY?

MBB charges 0.04% a year and MDY charges 0.23%, 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

MBB vs MDY: how they differ

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

iShares MBS ETF and SPDR S&P MidCap 400 ETF Trust.

What they hold in common

By the books each fund has filed, MBB and MDY 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 MBB	Only in MDY
Freddie Mac 1.07%	TWILIO INC 0.86%
Government National Mortgage Association 0.97%	CARPENTER TECHNOLOGY CORP 0.85%
UMBS, TBA 0.85%	MKS INC 0.83%
Government National Mortgage Association 0.69%	CURTISS-WRIGHT CORP 0.77%
UMBS, TBA 0.66%	ENTEGRIS INC 0.76%
Government National Mortgage Association 0.56%	NVENT ELECTRIC PLC 0.76%
Government National Mortgage Association 0.55%	ATI INC 0.74%
Government National Mortgage Association 0.54%	ILLUMINA INC 0.73%

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.

MBB and MDY on the fields both publish, as of Sep 12, 2026. Source: ETFIQ.
	MBB iShares MBS ETF	MDY SPDR S&P MidCap 400 ETF Trust
Where it sits	Core index fund	Core index fund
Issuer	iShares	State Street
What it is	Mbs	S&P MidCap 400, book from IJH
Total return, 1 year	−0.1%	+13.0%
S&P 500 over the same days	+17.5%	+17.5%
Gap to the S&P 500	−17.6 pts	−4.5 pts
Expense ratio	0.04%	0.23%
Holdings	11144	400

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.

MDY in plain words

MDY is an index equity fund tracking the S&P MidCap 400. Over the year to Sep 11, 2026 it returned +13.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.23% 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 400 positions, with the top ten at 7.7%. It sat 5.3% below its high of Aug 14, 2026 on Sep 11, 2026.

Questions people ask

Which returned more over the last year, MBB or MDY?: In the year to Sep 12, 2026, with distributions reinvested, MBB returned −0.1% and MDY returned +13.0%, so MDY returned more. One year is one year; the longer windows are in the table.
Which is cheaper, MBB or MDY?: MBB charges 0.04% a year and MDY charges 0.23%, 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.

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

A comparison is not a recommendation. Standards and sources