Data as of Oct 28, 2026.
MBB vs MDY: Differences, Returns & Fees
Over the year to Oct 28, 2026, MBB returned −0.8% to MDY's +12.8%; 0% of their weight is in the same names.
askIQ about this page
askIQ about MBB and MDY
Net assets: $35.5bn on Oct 28, 2026 for iShares MBS ETF, and $25.9bn on Oct 27, 2026 for SPDR S&P MidCap 400 ETF Trust.
Pair scorecard
MBB costs 0.19 points a year less; their one-year returns differ by 13.6 points; MBB is 1.4 times larger.
| Measure | MBB | MDY |
|---|---|---|
| Return | ||
| Total return, 1 year | −0.8% | +12.8% |
| Drawdown | ||
| Below its high | 6.5%, high on Aug 14, 2026 | |
| Benchmark | ||
| What it tracks | Bloomberg U.S. MBS Index | S&P MidCap 400 Index |
| Cost and size | ||
| Expense ratio | 0.04% | 0.23% |
| Net assets, as of Oct 26, 2026 | $35.6bn | $25.8bn |
| Holdings | ||
| Holdings in common | 0% | |
| In the S&P 500, by weight | 0% | |
| Top ten holdings, share of the fund | 7.5% | |
Holdings in common uses holdings dated Oct 27, 2026. Method
What they share
By the books each fund has filed, MBB and MDY hold 0% of their money in the same securities at the same weight. Holdings dated Oct 27, 2026.
half
0% in common
Only in one fund ↓
Side by side
MBB and MDY on the fields both publish, as of Oct 28, 2026. Source: ETFIQ.
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.
MDY
MDY tracks the S&P MidCap 400. Over the year to Oct 28, 2026 it returned +12.8% with distributions reinvested, against +13.2% for its benchmark, the S&P MidCap 400 Index. The prospectus expense ratio is 0.23% a year. By its holdings published by its issuer for Oct 27, 2026, 0% of the fund by weight is stocks the S&P 500 also holds, across 401 positions, with the top ten at 7.5%. It sat 6.5% below its high of Aug 14, 2026 on Oct 28, 2026.
Questions people ask
- Which returned more over the last year, MBB or MDY?
- In the year to Oct 28, 2026, with distributions reinvested, MBB returned −0.8% and MDY +12.8%.
- Which is cheaper, MBB or MDY?
- MBB is cheaper, by 0.19 percentage points a year. That is about $19 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.
Cite this pageCitation, APA and Markdown
ETFIQ, MBB against MDY, data as of Oct 28, 2026. https://etfiq.com/compare/any/mbb-vs-mdy
ETFIQ. (Oct 28, 2026). MBB against MDY. Retrieved from https://etfiq.com/compare/any/mbb-vs-mdy
[MBB against MDY (ETFIQ, Oct 28, 2026)](https://etfiq.com/compare/any/mbb-vs-mdy)
Free to use with attribution for data ETFIQ computes; issuer data stays under its owner's terms.