IWM vs XBI: Holdings Overlap
iShares · 1941 holdings · $82.2B · as of 2026-03-31
XBIState Street® SPDR® S&P® Biotech ETF
State Street (SPDR) · 149 holdings · $10.0B · as of 2026-08-06
Holdings snapshots are 128 days apart (IWM: 2026-03-31, XBI: 2026-08-06). Weights and index membership change between snapshots, so the true current overlap is typically higher than shown. For funds tracking the same index, the gap can be 5–15 points.
How similar are IWM and XBI?
iShares Russell 2000 ETF (IWM, by iShares) holds 1941 positions; State Street® SPDR® S&P® Biotech ETF (XBI, by State Street (SPDR)) holds 149. They have 112 holdings in common, and by portfolio weight the two funds are 7.9% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 7.9%Sum of the smaller weight of each shared holding
- Shared Holdings
- 112IWM holds 1941 · XBI holds 149
- Weight in Shared Holdings
- IWM 8%·XBI 72%Share of each fund's weight in stocks both funds own
Based on each fund's latest official holdings. How is this calculated?
What makes each fund different
Only in IWM
1829 of 1941 positions (91.8% of the fund) are not held by XBI. Showing the top 30 by weight.
Only in XBI
37 of 149 positions (28.2% of the fund) are not held by IWM. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWM | XBI |
|---|---|---|
| Health Care | 16.6% | 95.5% |
| Industrials | 17.9% | 0.0% |
| Financials | 15.3% | 0.0% |
| Information Technology | 13.6% | 0.0% |
| Consumer Discretionary | 8.0% | 0.0% |
| Other Sectors | 22.7% | 0.0% |
| Unclassified | 5.5% | 4.6% |
Share of each fund's portfolio weight by GICS-style sector, compiled from issuer fund data and our own classification of the holdings, not the issuers' published sector charts. “Unclassified” is weight we could not classify (5% of IWM, 5% of XBI).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IWM | +1.8% | +23.0% | +38.6% | +17.1% | +7.5% | +10.8% | 0.88% |
| XBI | -4.0% | +29.2% | +85.3% | +26.3% | +4.5% | +9.5% | 0.36% |
Total returns including dividends, from adjusted daily closes as of 2026-08-07. 3Y/5Y/10Y are annualized. Yield is trailing-12-month distributions over the last close. Past performance does not predict future results.
Project the growth of $10,000 in IWM vs XBI →
Shared Holdings(112)
The top 10 shared positions account for 33% of the overlap, led by BBIO, MDGL and ARWR.
 BBIOBridgebio Pharma Inc COM | 0.40% | 1.19% | 0.40% |
|---|---|---|---|
 MDGLMadrigal Pharmaceuticals Inc COM | 0.30% | 1.05% | 0.30% |
 ARWRArrowhead Pharmaceuticals Inc COM | 0.29% | 1.17% | 0.29% |
 PRAXPraxis Precision Medicines Inc COM NEW | 0.28% | 1.49% | 0.28% |
 CYTKCytokinetics Incorporated | 0.27% | 1.17% | 0.27% |
 PCVXVaxcyte Inc COM | 0.25% | 1.25% | 0.25% |
 KRYSKrystal Biotech Inc COM | 0.22% | 1.00% | 0.22% |
 PTGXProtagonist Therapeutics Inc COM | 0.21% | 1.34% | 0.21% |
 ALKSAlkermes PLC COM USD0.01 | 0.20% | 1.07% | 0.20% |
 COGTCogent Biosciences Inc. COM | 0.19% | 1.29% | 0.19% |
 PTCTPTC Therapeutics, Inc. COM | 0.18% | 0.93% | 0.18% |
 TGTXTG Therapeutics Inc COM | 0.16% | 1.03% | 0.16% |
 KYMRKymera Therapeutics Inc COM | 0.16% | 1.31% | 0.16% |
 RYTMRhythm Pharmaceuticals Inc COM | 0.16% | 1.26% | 0.16% |
 1CGCRISPR Therapeutics AG COM CHF0.03 | 0.15% | 1.01% | 0.15% |
 SRRKScholar Rock Holding Corp. COM | 0.15% | 1.15% | 0.15% |
 CGONCG Oncology Inc. COM | 0.14% | 1.32% | 0.14% |
 CELCCelcuity Inc. COM | 0.14% | 1.02% | 0.14% |
 MIRMMirum Pharmaceuticals Inc. COM | 0.13% | 0.97% | 0.13% |
 APGEApogee Therapeutics Inc. COM | 0.12% | 1.57% | 0.12% |
 SYRESpyre Therapeutics Inc COM NEW | 0.12% | 1.33% | 0.12% |
 ERASErasca Inc COM | 0.10% | 1.32% | 0.10% |
 DNTHDianthus Therapeutics Inc COM | 0.10% | 1.39% | 0.10% |
 TWSTTwist Bioscience Corporation COM | 0.10% | 1.56% | 0.10% |
 ACADAcadia Pharmaceuticals Inc COM | 0.10% | 1.10% | 0.10% |
Frequently Asked Questions
How much do IWM and XBI overlap?
IWM and XBI overlap by 7.9% of portfolio weight. They share 112 holdings (IWM holds 1941 positions and XBI holds 149), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWM and XBI?
The two portfolios are 7.9% identical by weight. Owning both is not redundant. Most of each portfolio is distinct, so the funds can serve different roles.
What are the biggest shared holdings of IWM and XBI?
The largest positions held by both funds are BBIO, MDGL, ARWR, PRAX and CYTK. Together the top 10 shared positions account for 33% of the total overlap.
What does IWM own that XBI doesn't?
1829 positions (91.8% of IWM) are unique to IWM, led by BE, CDE and FN. In the other direction, 37 positions (28.2% of XBI) are unique to XBI.