IBB vs VBK: Holdings Overlap
iShares · 254 holdings · $9.3B · as of 2026-03-31
VBKVanguard Small-cap Growth Index Fund
Vanguard · 551 holdings · $24.3B · as of 2026-03-31
How similar are IBB and VBK?
iShares Biotechnology ETF (IBB, by iShares) holds 254 positions; Vanguard Small-cap Growth Index Fund (VBK, by Vanguard) holds 551. They have 57 holdings in common, and by portfolio weight the two funds are 11.0% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 11.0%Sum of the smaller weight of each shared holding
- Shared Holdings
- 57IBB holds 254 · VBK holds 551
- Weight in Shared Holdings
- IBB 32%·VBK 11%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
197 of 254 positions (67.5% of the fund) are not held by VBK. Showing the top 30 by weight.
Only in VBK
494 of 551 positions (88.7% of the fund) are not held by IBB. Showing the top 30 by weight.
Sector Breakdown
| Sector | IBB | VBK |
|---|---|---|
| Health Care | 91.0% | 16.1% |
| Industrials | 0.0% | 24.6% |
| Information Technology | 0.0% | 21.6% |
| Consumer Discretionary | 0.0% | 9.9% |
| Financials | 0.0% | 6.1% |
| Other Sectors | 0.0% | 20.6% |
| Unclassified | 8.9% | 0.9% |
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, 1% of VBK).
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% |
| VBK | +1.8% | +19.6% | +29.4% | +16.6% | +5.3% | +11.4% | 0.42% |
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 VBK →
Shared Holdings(57)
The top 10 shared positions account for 46% of the overlap, led by NTRA, RVMD and INSM.
 NTRANatera Inc. COM | 2.41% | 0.88% | 0.88% |
|---|---|---|---|
 RVMDRevolution Medicines Inc COM | 1.54% | 0.61% | 0.61% |
 INSMInsmed Inc COM PAR $.01 | 3.20% | 0.59% | 0.59% |
 INCYIncyte Corporation. COM | 1.70% | 0.53% | 0.53% |
 NBIXNeurocrine Biosciences Inc COM | 1.18% | 0.44% | 0.44% |
 BBIOBridgebio Pharma Inc COM | 1.13% | 0.43% | 0.43% |
 ROIVRoivant Sciences Ltd SHS | 1.24% | 0.43% | 0.43% |
 IONSIonis Pharmaceuticals, Inc. COM | 1.11% | 0.39% | 0.39% |
 MEDPMedpace Holdings Inc. COM | 1.00% | 0.36% | 0.36% |
 BMRNBiomarin Pharmaceutical Inc. COM | 0.98% | 0.36% | 0.36% |
 EXELExelixis, Inc. COM | 0.99% | 0.35% | 0.35% |
 MDGLMadrigal Pharmaceuticals Inc COM | 1.00% | 0.32% | 0.32% |
 PCVXVaxcyte Inc COM | 0.75% | 0.28% | 0.28% |
 ARWRArrowhead Pharmaceuticals Inc COM | 0.75% | 0.28% | 0.28% |
 TECHBio-Techne Corp COM | 0.74% | 0.27% | 0.27% |
 CYTKCytokinetics Incorporated | 0.73% | 0.27% | 0.27% |
 HALOHalozyme Therapeutics Inc COM | 0.69% | 0.25% | 0.25% |
 AXSMAxsome Therapeutics Inc. COM | 0.66% | 0.25% | 0.25% |
 KRYSKrystal Biotech Inc COM | 0.60% | 0.23% | 0.23% |
 PTGXProtagonist Therapeutics Inc COM | 0.58% | 0.22% | 0.22% |
 ACLXArcellx Inc COMMON STOCK | 0.47% | 0.22% | 0.22% |
 RGENRepligen Corporation COM | 0.58% | 0.21% | 0.21% |
 RYTMRhythm Pharmaceuticals Inc COM | 0.51% | 0.20% | 0.20% |
 ALKSAlkermes PLC COM USD0.01 | 0.53% | 0.20% | 0.20% |
 PTCTPTC Therapeutics, Inc. COM | 0.50% | 0.19% | 0.19% |
Frequently Asked Questions
How much do IBB and VBK overlap?
IBB and VBK overlap by 11.0% of portfolio weight. They share 57 holdings (IBB holds 254 positions and VBK holds 551), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IBB and VBK?
The two portfolios are 11.0% 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 IBB and VBK?
The largest positions held by both funds are NTRA, RVMD, INSM, INCY and NBIX. Together the top 10 shared positions account for 46% of the total overlap.
What does IBB own that VBK doesn't?
197 positions (67.5% of IBB) are unique to IBB, led by GILD, AMGN and VRTX. In the other direction, 494 positions (88.7% of VBK) are unique to VBK.