IWO vs VIOO: Holdings Overlap
IWOiShares Russell 2000 Growth ETF
iShares · 1101 holdings · $14.8B · 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 (IWO: 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 IWO and VIOO?
iShares Russell 2000 Growth ETF (IWO, by iShares) holds 1101 positions; Vanguard S&P Small-cap 600 Index Fund (VIOO, by Vanguard) holds 603. They have 296 holdings in common, and by portfolio weight the two funds are 36.7% identical. In practical terms the pair is moderately overlapping; they share a meaningful core, but each fund adds distinct exposure.
- Overlap by Weight
- 36.7%Sum of the smaller weight of each shared holding
- Shared Holdings
- 296IWO holds 1101 · VIOO holds 603
- Weight in Shared Holdings
- IWO 40%·VIOO 51%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 IWO
805 of 1101 positions (60.1% of the fund) are not held by VIOO. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWO | VIOO |
|---|---|---|
| Industrials | 23.7% | 17.2% |
| Health Care | 23.1% | 11.0% |
| Information Technology | 19.0% | 15.9% |
| Financials | 8.6% | 17.6% |
| Consumer Discretionary | 7.3% | 12.9% |
| Other Sectors | 14.1% | 25.2% |
| Unclassified | 4.0% | 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 (4% of IWO, 0% of VIOO).
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IWO | +1.2% | +21.0% | +34.7% | +17.5% | +5.9% | +11.0% | 0.42% |
| 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 IWO vs VIOO →
Shared Holdings(296)
The top 10 shared positions account for 12% of the overlap, led by VIAV, AGX and SMTC.
 VIAVViavi Solutions Inc COM | 0.51% | 0.66% | 0.51% |
|---|---|---|---|
 AGXArgan Inc COM | 0.49% | 0.54% | 0.49% |
 SMTCSemtech Corporation COM | 0.48% | 0.83% | 0.48% |
 ESEESCO Technologies Inc. COM | 0.49% | 0.44% | 0.44% |
 KRYSKrystal Biotech Inc COM | 0.43% | 0.47% | 0.43% |
 ZWSZurn Elkay Water Solutions Corporation COM | 0.45% | 0.41% | 0.41% |
 PRIMPrimoris Services Corp. COM | 0.49% | 0.40% | 0.40% |
 SNEXStoneX Group Inc COM | 0.40% | 0.47% | 0.40% |
 LUMNLumen Technologies Inc COM | 0.39% | 0.61% | 0.39% |
 RHPRyman Hospitality Properties Inc COM | 0.38% | 0.43% | 0.38% |
 FSSFederal Signal Corp. COM | 0.44% | 0.38% | 0.38% |
 FORMFormfactor Inc COM | 0.38% | 0.57% | 0.38% |
 BTSGBrightSpring Health Services Inc. COM | 0.37% | 0.48% | 0.37% |
 EATBrinker International, Inc. COM | 0.42% | 0.36% | 0.36% |
 GKOSGlaukos Corp. COM | 0.40% | 0.35% | 0.35% |
 POWLPowell Industries Inc. COM | 0.35% | 0.47% | 0.35% |
 AROCArchrock Inc COM | 0.40% | 0.34% | 0.34% |
 PTGXProtagonist Therapeutics Inc COM | 0.41% | 0.34% | 0.34% |
 PLXSPlexus Corp COM | 0.34% | 0.42% | 0.34% |
 KGSKodiak Gas Services Inc. COM | 0.33% | 0.37% | 0.33% |
 PIPRPiper Sandler Companies COM NEW | 0.36% | 0.31% | 0.31% |
 GVAGranite Construction Inc COM | 0.30% | 0.35% | 0.30% |
 TGTXTG Therapeutics Inc COM | 0.32% | 0.30% | 0.30% |
 BOOTBoot Barn Holdings Inc COM | 0.30% | 0.30% | 0.30% |
 CWSTCasella Waste Systems, Inc., Class A | 0.34% | 0.30% | 0.30% |
Showing the top 250 of 296 shared holdings by overlap weight.
Frequently Asked Questions
How much do IWO and VIOO overlap?
IWO and VIOO overlap by 36.7% of portfolio weight. They share 296 holdings (IWO holds 1101 positions and VIOO holds 603), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWO and VIOO?
The two portfolios are 36.7% 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 IWO and VIOO?
The largest positions held by both funds are VIAV, AGX, SMTC, ESE and KRYS. Together the top 10 shared positions account for 12% of the total overlap.
What does IWO own that VIOO doesn't?
805 positions (60.1% of IWO) are unique to IWO, led by BE, FN and CRDO. In the other direction, 307 positions (48.4% of VIOO) are unique to VIOO.