ITOT vs XBI: Holdings Overlap
ITOTiShares Core S&P Total U.S. Stock Market ETF
iShares · 2487 holdings · $97.6B · 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 (ITOT: 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 ITOT and XBI?
iShares Core S&P Total U.S. Stock Market ETF (ITOT, by iShares) holds 2487 positions; State Street® SPDR® S&P® Biotech ETF (XBI, by State Street (SPDR)) holds 149. They have 134 holdings in common, and by portfolio weight the two funds are 2.3% identical. In practical terms the pair is essentially distinct, holding almost none of the same securities.
- Overlap by Weight
- 2.3%Sum of the smaller weight of each shared holding
- Shared Holdings
- 134ITOT holds 2487 · XBI holds 149
- Weight in Shared Holdings
- ITOT 2%·XBI 97%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 ITOT
2353 of 2487 positions (97.4% of the fund) are not held by XBI. Showing the top 30 by weight.
Sector Breakdown
| Sector | ITOT | XBI |
|---|---|---|
| Health Care | 9.9% | 95.5% |
| Information Technology | 30.8% | 0.0% |
| Financials | 12.9% | 0.0% |
| Industrials | 10.2% | 0.0% |
| Consumer Discretionary | 9.9% | 0.0% |
| Other Sectors | 26.0% | 0.0% |
| Unclassified | 0.1% | 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 (0% of ITOT, 5% of XBI).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| ITOT | +3.3% | +14.6% | +24.1% | +20.9% | +12.3% | +14.9% | 0.97% |
| 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 ITOT vs XBI →
Shared Holdings(134)
The top 10 shared positions account for 74% of the overlap, led by ABBV, AMGN and GILD.
 ABBVAbbVie Inc. COM | 0.61% | 1.05% | 0.61% |
|---|---|---|---|
 AMGNAmgen Inc. COM | 0.30% | 1.16% | 0.30% |
 GILDGilead Sciences Inc. COM | 0.27% | 1.04% | 0.27% |
 VRTXVertex Pharmaceuticals Incorporated COM | 0.18% | 1.07% | 0.18% |
 REGNRegeneron Pharmaceuticals, Inc. COM | 0.12% | 1.24% | 0.12% |
 ALNYAlnylam Pharmaceuticals Inc. COM | 0.07% | 0.72% | 0.07% |
 INSMInsmed Inc COM PAR $.01 | 0.06% | 1.39% | 0.06% |
 NTRANatera Inc. COM | 0.04% | 1.18% | 0.04% |
 BIIBBiogen Inc COM | 0.04% | 1.03% | 0.04% |
 UTHRUnited Therapeutics Corporation COM | 0.04% | 0.95% | 0.04% |
 RVMDRevolution Medicines Inc COM | 0.03% | 1.33% | 0.03% |
 MRNAModerna Inc COM | 0.03% | 1.13% | 0.03% |
 INCYIncyte Corporation. COM | 0.02% | 1.09% | 0.02% |
 NBIXNeurocrine Biosciences Inc COM | 0.02% | 0.96% | 0.02% |
 BBIOBridgebio Pharma Inc COM | 0.02% | 1.19% | 0.02% |
 ROIVRoivant Sciences Ltd SHS | 0.02% | 1.19% | 0.02% |
 IONSIonis Pharmaceuticals, Inc. COM | 0.02% | 0.72% | 0.02% |
 EXELExelixis, Inc. COM | 0.02% | 0.96% | 0.02% |
 BMRNBiomarin Pharmaceutical Inc. COM | 0.02% | 1.06% | 0.02% |
 MDGLMadrigal Pharmaceuticals Inc COM | 0.02% | 1.05% | 0.02% |
 ARWRArrowhead Pharmaceuticals Inc COM | 0.01% | 1.17% | 0.01% |
 PRAXPraxis Precision Medicines Inc COM NEW | 0.01% | 1.49% | 0.01% |
 CYTKCytokinetics Incorporated | 0.01% | 1.17% | 0.01% |
 PCVXVaxcyte Inc COM | 0.01% | 1.25% | 0.01% |
 HALOHalozyme Therapeutics Inc COM | 0.01% | 1.18% | 0.01% |
Frequently Asked Questions
How much do ITOT and XBI overlap?
ITOT and XBI overlap by 2.3% of portfolio weight. They share 134 holdings (ITOT holds 2487 positions and XBI holds 149), based on each fund's latest SEC-reported holdings.
Is it redundant to own both ITOT and XBI?
The two portfolios are 2.3% identical by weight. Owning both is genuine diversification: the funds hold almost none of the same securities.
What are the biggest shared holdings of ITOT and XBI?
The largest positions held by both funds are ABBV, AMGN, GILD, VRTX and REGN. Together the top 10 shared positions account for 74% of the total overlap.
What does ITOT own that XBI doesn't?
2353 positions (97.4% of ITOT) are unique to ITOT, led by NVDA, AAPL and MSFT. In the other direction, 15 positions (2.8% of XBI) are unique to XBI.