IWO vs XBI: Holdings Overlap
IWOiShares Russell 2000 Growth ETF
iShares · 1101 holdings · $14.8B · 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 (IWO: 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 IWO and XBI?
iShares Russell 2000 Growth ETF (IWO, by iShares) holds 1101 positions; State Street® SPDR® S&P® Biotech ETF (XBI, by State Street (SPDR)) holds 149. They have 76 holdings in common, and by portfolio weight the two funds are 10.3% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 10.3%Sum of the smaller weight of each shared holding
- Shared Holdings
- 76IWO holds 1101 · XBI holds 149
- Weight in Shared Holdings
- IWO 10%·XBI 53%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 IWO
1025 of 1101 positions (89.5% of the fund) are not held by XBI. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWO | XBI |
|---|---|---|
| Health Care | 23.1% | 95.5% |
| Industrials | 23.7% | 0.0% |
| Information Technology | 19.0% | 0.0% |
| Financials | 8.6% | 0.0% |
| Consumer Discretionary | 7.3% | 0.0% |
| Other Sectors | 14.1% | 0.0% |
| Unclassified | 4.0% | 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 (4% of IWO, 5% of XBI).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IWO | +1.2% | +21.0% | +34.7% | +17.5% | +5.9% | +11.0% | 0.42% |
| 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 IWO vs XBI →
Shared Holdings(76)
The top 10 shared positions account for 43% of the overlap, led by BBIO, MDGL and ARWR.
 BBIOBridgebio Pharma Inc COM | 0.79% | 1.19% | 0.79% |
|---|---|---|---|
 MDGLMadrigal Pharmaceuticals Inc COM | 0.60% | 1.05% | 0.60% |
 ARWRArrowhead Pharmaceuticals Inc COM | 0.57% | 1.17% | 0.57% |
 KRYSKrystal Biotech Inc COM | 0.43% | 1.00% | 0.43% |
 PTGXProtagonist Therapeutics Inc COM | 0.41% | 1.34% | 0.41% |
 COGTCogent Biosciences Inc. COM | 0.35% | 1.29% | 0.35% |
 TGTXTG Therapeutics Inc COM | 0.32% | 1.03% | 0.32% |
 KYMRKymera Therapeutics Inc COM | 0.32% | 1.31% | 0.32% |
 RYTMRhythm Pharmaceuticals Inc COM | 0.31% | 1.26% | 0.31% |
 PTCTPTC Therapeutics, Inc. COM | 0.29% | 0.93% | 0.29% |
 ALKSAlkermes PLC COM USD0.01 | 0.29% | 1.07% | 0.29% |
 CGONCG Oncology Inc. COM | 0.27% | 1.32% | 0.27% |
 SRRKScholar Rock Holding Corp. COM | 0.26% | 1.15% | 0.26% |
 MIRMMirum Pharmaceuticals Inc. COM | 0.26% | 0.97% | 0.26% |
 CELCCelcuity Inc. COM | 0.26% | 1.02% | 0.26% |
 APGEApogee Therapeutics Inc. COM | 0.25% | 1.57% | 0.25% |
 TWSTTwist Bioscience Corporation COM | 0.19% | 1.56% | 0.19% |
 ACADAcadia Pharmaceuticals Inc COM | 0.19% | 1.10% | 0.19% |
 ARQTArcutis Biotherapeutics Inc. COM | 0.17% | 0.75% | 0.17% |
 VCYTVeracyte Inc COM | 0.17% | 0.67% | 0.17% |
 VERAVera Therapeutics, Inc., Class A | 0.17% | 0.82% | 0.17% |
 SYRESpyre Therapeutics Inc COM NEW | 0.16% | 1.33% | 0.16% |
 TVTXTravere Therapeutics Inc COM | 0.15% | 1.29% | 0.15% |
 BEAMBeam Therapeutics Inc. COM | 0.15% | 0.89% | 0.15% |
 IMNMImmunome Inc COM | 0.15% | 0.75% | 0.15% |
Frequently Asked Questions
How much do IWO and XBI overlap?
IWO and XBI overlap by 10.3% of portfolio weight. They share 76 holdings (IWO holds 1101 positions and XBI holds 149), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWO and XBI?
The two portfolios are 10.3% 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 IWO and XBI?
The largest positions held by both funds are BBIO, MDGL, ARWR, KRYS and PTGX. Together the top 10 shared positions account for 43% of the total overlap.
What does IWO own that XBI doesn't?
1025 positions (89.5% of IWO) are unique to IWO, led by BE, FN and CRDO. In the other direction, 73 positions (47.1% of XBI) are unique to XBI.