Data as of Sep 12, 2026. Both funds on the fields they both publish, from the same sources.
IWM vs XBI: how they differ
IWM and XBI hold 9% of their weight in the same names, and XBI returned more over the year.
iShares Russell 2000 ETF and State Street(R) SPDR(R) S&P(R) Biotech ETF.
What they hold in common
By the books each fund has filed, IWM and XBI hold 9% of their money in the same securities at the same weight.
| Holding | IWM | XBI |
|---|---|---|
| Cytokinetics, Inc. | 0.35% | 1.18% |
| Krystal Biotech, Inc. | 0.30% | 1.10% |
| Praxis Precision Medicines, Inc. | 0.26% | 1.29% |
| TG Therapeutics, Inc. | 0.25% | 1.09% |
| Vaxcyte, Inc. | 0.24% | 1.19% |
| Protagonist Therapeutics, Inc. | 0.23% | 1.08% |
| Kymera Therapeutics, Inc. | 0.22% | 1.36% |
| PTC Therapeutics, Inc. | 0.21% | 1.03% |
| Nuvalent, Inc. | 0.21% | 0.93% |
| Spyre Therapeutics, Inc. | 0.20% | 1.10% |
| Cogent Biosciences, Inc. | 0.20% | 1.15% |
| Twist Bioscience Corp. | 0.20% | 1.41% |
| Only in IWM | Only in XBI |
|---|---|
| Moog, Inc. 0.38% | Moderna Inc 1.41% |
| Hut 8 Corp. 0.37% | Viking Therapeutics Inc 1.31% |
| Viasat, Inc. 0.35% | Revolution Medicines Inc 1.21% |
| BrightSpring Health Services, Inc. 0.35% | Natera Inc 1.17% |
| MaxLinear, Inc. 0.34% | Roivant Sciences Ltd 1.16% |
| Argan, Inc. 0.34% | Alkermes PLC 1.11% |
| UMB Financial Corp. 0.33% | Insmed Inc 1.08% |
| JFrog Ltd. 0.31% | Arrowhead Pharmaceuticals Inc 1.07% |
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.
| IWM iShares Russell 2000 ETF | XBI State Street(R) SPDR(R) S&P(R) Biotech ETF | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | iShares | State Street |
| What it is | Russell 2000 | SPDR S&P Biotech |
| Total return, 1 year | +21.2% | +64.0% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | +3.7 pts | +46.5 pts |
| Expense ratio | 0.19% | 0.35% |
| Already in the S&P 500 | 0.0% | 8.5% |
| Holdings | 2014 | 150 |
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.
XBI in plain words
XBI is an index equity fund tracking the SPDR S&P Biotech. Over the year to Sep 11, 2026 it returned +64.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.35% a year. By its holdings filed for Jun 30, 2026, 8% of the fund by weight is stocks the S&P 500 also holds, across 150 positions, with the top ten at 13.3%. It sat 9.6% below its high of Feb 8, 2021 on Sep 11, 2026.
Questions people ask
- Which returned more over the last year, IWM or XBI?
- In the year to Sep 12, 2026, with distributions reinvested, IWM returned +21.2% and XBI returned +64.0%, so XBI returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, IWM or XBI?
- IWM charges 0.19% a year and XBI charges 0.35%, so IWM is cheaper. Fees come from each fund's prospectus.
- How much do IWM and XBI overlap with the S&P 500?
- By their latest filed holdings, 0% of IWM and 8% of XBI by weight is stocks the S&P 500 already holds. Between the two funds, 9% of their books are the same securities at the same weight.
Other comparisons
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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.
Cite this page. ETFIQ, IWM against XBI, data as of Sep 12, 2026. https://etfiq.com/compare/any/IWM-XBI Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources