IBB vs SLYG: Holdings Overlap
iShares · 254 holdings · $9.3B · as of 2026-03-31
SLYGState Street® SPDR® S&P 600™ Small Cap Growth ETF
State Street (SPDR) · 349 holdings · $5.3B · as of 2026-08-06
Holdings snapshots are 128 days apart (IBB: 2026-03-31, SLYG: 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 IBB and SLYG?
iShares Biotechnology ETF (IBB, by iShares) holds 254 positions; State Street® SPDR® S&P 600™ Small Cap Growth ETF (SLYG, by State Street (SPDR)) holds 349. They have 12 holdings in common, and by portfolio weight the two funds are 2.8% identical. In practical terms the pair is essentially distinct, holding almost none of the same securities.
- Overlap by Weight
- 2.8%Sum of the smaller weight of each shared holding
- Shared Holdings
- 12IBB holds 254 · SLYG holds 349
- Weight in Shared Holdings
- IBB 3%·SLYG 4%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
242 of 254 positions (96.9% of the fund) are not held by SLYG. Showing the top 30 by weight.
Sector Breakdown
| Sector | IBB | SLYG |
|---|---|---|
| Health Care | 91.0% | 15.0% |
| Industrials | 0.0% | 21.9% |
| Financials | 0.0% | 15.7% |
| Information Technology | 0.0% | 13.8% |
| Consumer Discretionary | 0.0% | 12.0% |
| 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 SLYG).
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% |
| SLYG | +1.2% | +25.9% | +33.5% | +15.2% | +6.7% | +11.2% | 0.64% |
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 SLYG →
Shared Holdings(12)
The top 10 shared positions account for 100% of the overlap, led by PTGX, ALKS and PTCT.
 PTGXProtagonist Therapeutics Inc COM | 0.58% | 0.99% | 0.58% |
|---|---|---|---|
 ALKSAlkermes PLC COM USD0.01 | 0.53% | 0.90% | 0.53% |
 PTCTPTC Therapeutics, Inc. COM | 0.50% | 0.66% | 0.50% |
 ACADAcadia Pharmaceuticals Inc COM | 0.34% | 0.40% | 0.34% |
 VCYTVeracyte Inc COM | 0.23% | 0.41% | 0.23% |
 ADMAAdma Biologics Inc COM | 0.19% | 0.26% | 0.19% |
 RCUSArcus Biosciences Inc. COM | 0.16% | 0.17% | 0.16% |
 VCELVericel Corporation COM | 0.15% | 0.26% | 0.15% |
 SRPTSarepta Therapeutics Inc COM | 0.20% | 0.12% | 0.12% |
 VIRVIR Biotechnology Inc COM | 0.08% | 0.05% | 0.05% |
 2200963DOmniAb Inc. USD0.0001 A (USD12.5 VESTING) | 0.00% | 0.00% | 0.00% |
 2200964DOmniAb Inc. USD0.0001 A (USD15 VESTING) | 0.00% | 0.00% | 0.00% |
Frequently Asked Questions
How much do IBB and SLYG overlap?
IBB and SLYG overlap by 2.8% of portfolio weight. They share 12 holdings (IBB holds 254 positions and SLYG holds 349), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IBB and SLYG?
The two portfolios are 2.8% 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 SLYG?
The largest positions held by both funds are PTGX, ALKS, PTCT, ACAD and VCYT. Together the top 10 shared positions account for 100% of the total overlap.
What does IBB own that SLYG doesn't?
242 positions (96.9% of IBB) are unique to IBB, led by GILD, AMGN and VRTX. In the other direction, 337 positions (95.5% of SLYG) are unique to SLYG.