IBB vs ITOT: Holdings Overlap
iShares · 254 holdings · $9.3B · as of 2026-03-31
ITOTiShares Core S&P Total U.S. Stock Market ETF
iShares · 2487 holdings · $97.6B · as of 2026-03-31
How similar are IBB and ITOT?
iShares Biotechnology ETF (IBB, by iShares) holds 254 positions; iShares Core S&P Total U.S. Stock Market ETF (ITOT, by iShares) holds 2487. They have 182 holdings in common, and by portfolio weight the two funds are 1.9% identical. In practical terms the pair is essentially distinct, holding almost none of the same securities.
- Overlap by Weight
- 1.9%Sum of the smaller weight of each shared holding
- Shared Holdings
- 182IBB holds 254 · ITOT holds 2487
- Weight in Shared Holdings
- IBB 88%·ITOT 2%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 IBB
72 of 254 positions (11.9% of the fund) are not held by ITOT. Showing the top 30 by weight.
Sector Breakdown
| Sector | IBB | ITOT |
|---|---|---|
| Health Care | 91.0% | 9.9% |
| Information Technology | 0.0% | 30.8% |
| Financials | 0.0% | 12.9% |
| Industrials | 0.0% | 10.2% |
| Consumer Discretionary | 0.0% | 9.9% |
| Other Sectors | 0.0% | 26.0% |
| Unclassified | 8.9% | 0.1% |
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 (9% of IBB, 0% of ITOT).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IBB | -0.3% | +17.3% | +51.0% | +16.4% | +3.1% | +7.4% | 0.21% |
| ITOT | +3.3% | +14.6% | +24.1% | +20.9% | +12.3% | +14.9% | 0.97% |
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 IBB vs ITOT →
Shared Holdings(182)
The top 10 shared positions account for 60% of the overlap, led by AMGN, GILD and VRTX.
 AMGNAmgen, Inc. | 7.51% | 0.30% | 0.30% |
|---|---|---|---|
 GILDGilead Sciences, Inc. | 7.75% | 0.27% | 0.27% |
 VRTXVertex Pharmaceuticals, Inc. | 7.44% | 0.18% | 0.18% |
 REGNRegeneron Pharmaceuticals, Inc. | 7.21% | 0.12% | 0.12% |
 ALNYAlnylam Pharmaceuticals, Inc. | 3.99% | 0.07% | 0.07% |
 INSMInsmed, Inc. | 3.20% | 0.06% | 0.06% |
 NTRANatera, Inc. | 2.41% | 0.04% | 0.04% |
 BIIBBiogen, Inc. | 2.46% | 0.04% | 0.04% |
 UTHRUnited Therapeutics Corp. | 2.30% | 0.04% | 0.04% |
 ILMNIllumina, Inc. | 1.68% | 0.03% | 0.03% |
 RVMDRevolution Medicines, Inc. | 1.54% | 0.03% | 0.03% |
 MRNAModerna, Inc. | 1.68% | 0.03% | 0.03% |
 INCYIncyte Corp. | 1.70% | 0.02% | 0.02% |
 NBIXNeurocrine Biosciences, Inc. | 1.18% | 0.02% | 0.02% |
 BBIOBridgebio Pharma, Inc. | 1.13% | 0.02% | 0.02% |
 ROIVRoivant Sciences Ltd. | 1.24% | 0.02% | 0.02% |
 IONSIonis Pharmaceuticals, Inc. | 1.11% | 0.02% | 0.02% |
 EXELExelixis, Inc. | 0.99% | 0.02% | 0.02% |
 BMRNBioMarin Pharmaceutical, Inc. | 0.98% | 0.02% | 0.02% |
 MEDPMedpace Holdings, Inc. | 1.00% | 0.02% | 0.02% |
 MDGLMadrigal Pharmaceuticals, Inc. | 1.00% | 0.02% | 0.02% |
 CRLCharles River Laboratories International, Inc. | 0.77% | 0.01% | 0.01% |
 ARWRArrowhead Pharmaceuticals, Inc. | 0.75% | 0.01% | 0.01% |
 PRAXPraxis Precision Medicines, Inc. | 0.77% | 0.01% | 0.01% |
 TECHBio-Techne Corp. | 0.74% | 0.01% | 0.01% |
Frequently Asked Questions
How much do IBB and ITOT overlap?
IBB and ITOT overlap by 1.9% of portfolio weight. They share 182 holdings (IBB holds 254 positions and ITOT holds 2487), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IBB and ITOT?
The two portfolios are 1.9% identical by weight. Owning both is genuine diversification: the funds hold almost none of the same securities.
What are the biggest shared holdings of IBB and ITOT?
The largest positions held by both funds are AMGN, GILD, VRTX, REGN and ALNY. Together the top 10 shared positions account for 60% of the total overlap.
What does IBB own that ITOT doesn't?
72 positions (11.9% of IBB) are unique to IBB, led by ARGX, ONC and GMAB. In the other direction, 2305 positions (97.8% of ITOT) are unique to ITOT.