IWM vs VIOO: Holdings Overlap
iShares · 1941 holdings · $82.2B · as of 2026-03-31
VIOOVanguard S&P Small-cap 600 Index Fund
Vanguard · 603 holdings · $4.4B · as of 2026-05-31
Holdings snapshots are 61 days apart (IWM: 2026-03-31, VIOO: 2026-05-31). 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 IWM and VIOO?
iShares Russell 2000 ETF (IWM, by iShares) holds 1941 positions; Vanguard S&P Small-cap 600 Index Fund (VIOO, by Vanguard) holds 603. They have 533 holdings in common, and by portfolio weight the two funds are 42.3% identical. In practical terms the pair is moderately overlapping; they share a meaningful core, but each fund adds distinct exposure.
- Overlap by Weight
- 42.3%Sum of the smaller weight of each shared holding
- Shared Holdings
- 533IWM holds 1941 · VIOO holds 603
- Weight in Shared Holdings
- IWM 42%·VIOO 83%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 IWM
1408 of 1941 positions (57.3% of the fund) are not held by VIOO. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWM | VIOO |
|---|---|---|
| Industrials | 17.9% | 17.2% |
| Financials | 15.3% | 17.6% |
| Health Care | 16.6% | 11.0% |
| Information Technology | 13.6% | 15.9% |
| Consumer Discretionary | 8.0% | 12.9% |
| Other Sectors | 22.7% | 25.2% |
| Unclassified | 5.5% | 0.0% |
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 (5% of IWM, 0% of VIOO).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IWM | +1.8% | +23.0% | +38.6% | +17.1% | +7.5% | +10.8% | 0.88% |
| VIOO | +2.4% | +24.4% | +36.3% | +14.6% | +7.7% | +10.9% | 1.09% |
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 IWM vs VIOO →
Shared Holdings(533)
The top 10 shared positions account for 6% of the overlap, led by SM, PRIM and VIAV.
 SMSM Energy Co. COM | 0.26% | 0.41% | 0.26% |
|---|---|---|---|
 PRIMPrimoris Services Corp. COM | 0.26% | 0.40% | 0.26% |
 VIAVViavi Solutions Inc COM | 0.26% | 0.66% | 0.26% |
 FORMFormfactor Inc COM | 0.26% | 0.57% | 0.26% |
 AGXArgan Inc COM | 0.25% | 0.54% | 0.25% |
 ESEESCO Technologies Inc. COM | 0.25% | 0.44% | 0.25% |
 SMTCSemtech Corporation COM | 0.24% | 0.83% | 0.24% |
 JXNJackson Financial, Inc., Class A | 0.24% | 0.43% | 0.24% |
 SANMSanmina Corporation | 0.24% | 0.83% | 0.24% |
 ZWSZurn Elkay Water Solutions Corporation COM | 0.23% | 0.41% | 0.23% |
 JBTMJBT Marel Corp. COM | 0.23% | 0.41% | 0.23% |
 LUMNLumen Technologies Inc COM | 0.23% | 0.61% | 0.23% |
 FSSFederal Signal Corp. COM | 0.22% | 0.38% | 0.22% |
 KRYSKrystal Biotech Inc COM | 0.22% | 0.47% | 0.22% |
 TRNOTerreno Realty Corporation COM | 0.21% | 0.40% | 0.21% |
 NENoble Corporation PLC ORD SHS A | 0.21% | 0.34% | 0.21% |
 EATBrinker International, Inc. COM | 0.21% | 0.36% | 0.21% |
 IBPInstalled Building Products Inc COM | 0.21% | 0.28% | 0.21% |
 PTGXProtagonist Therapeutics Inc COM | 0.21% | 0.34% | 0.21% |
 EPRTEssential Properties Realty Trust Inc. COM | 0.20% | 0.38% | 0.20% |
 GKOSGlaukos Corp. COM | 0.20% | 0.35% | 0.20% |
 AROCArchrock Inc COM | 0.20% | 0.34% | 0.20% |
 SNEXStoneX Group Inc COM | 0.20% | 0.47% | 0.20% |
 ALKSAlkermes PLC COM USD0.01 | 0.20% | 0.35% | 0.20% |
 MGYMagnolia Oil & Gas Corporation CL A | 0.19% | 0.29% | 0.19% |
Showing the top 250 of 533 shared holdings by overlap weight.
Frequently Asked Questions
How much do IWM and VIOO overlap?
IWM and VIOO overlap by 42.3% of portfolio weight. They share 533 holdings (IWM holds 1941 positions and VIOO holds 603), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWM and VIOO?
The two portfolios are 42.3% identical by weight. Owning both is defensible: they share a meaningful core, but each fund adds exposure the other lacks.
What are the biggest shared holdings of IWM and VIOO?
The largest positions held by both funds are SM, PRIM, VIAV, FORM and AGX. Together the top 10 shared positions account for 6% of the total overlap.
What does IWM own that VIOO doesn't?
1408 positions (57.3% of IWM) are unique to IWM, led by BE, CDE and FN. In the other direction, 70 positions (17.2% of VIOO) are unique to VIOO.