IWO vs SPSM: Holdings Overlap
IWOiShares Russell 2000 Growth ETF
iShares · 1101 holdings · $14.8B · as of 2026-03-31
SPSMState Street® SPDR® Portfolio S&P 600™ Small Cap ETF
State Street (SPDR) · 604 holdings · $17.3B · as of 2026-08-06
Holdings snapshots are 128 days apart (IWO: 2026-03-31, SPSM: 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 IWO and SPSM?
iShares Russell 2000 Growth ETF (IWO, by iShares) holds 1101 positions; State Street® SPDR® Portfolio S&P 600™ Small Cap ETF (SPSM, by State Street (SPDR)) holds 604. They have 297 holdings in common, and by portfolio weight the two funds are 35.7% identical. In practical terms the pair is moderately overlapping; they share a meaningful core, but each fund adds distinct exposure.
- Overlap by Weight
- 35.7%Sum of the smaller weight of each shared holding
- Shared Holdings
- 297IWO holds 1101 · SPSM holds 604
- Weight in Shared Holdings
- IWO 39%·SPSM 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
804 of 1101 positions (60.8% of the fund) are not held by SPSM. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWO | SPSM |
|---|---|---|
| Industrials | 23.7% | 17.4% |
| Health Care | 23.1% | 10.6% |
| Information Technology | 19.0% | 12.8% |
| Financials | 8.6% | 19.0% |
| Consumer Discretionary | 7.3% | 13.9% |
| Other Sectors | 14.1% | 25.1% |
| Unclassified | 4.0% | 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 (4% of IWO, 1% of SPSM).
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% |
| SPSM | +2.4% | +24.5% | +36.5% | +14.6% | +7.7% | +10.9% | 1.36% |
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 SPSM →
Shared Holdings(297)
The top 10 shared positions account for 12% of the overlap, led by ESE, AGX and FSS.
 ESEESCO Technologies Inc. COM | 0.49% | 0.46% | 0.46% |
|---|---|---|---|
 AGXArgan Inc COM | 0.49% | 0.45% | 0.45% |
 FSSFederal Signal Corp. COM | 0.44% | 0.43% | 0.43% |
 ZWSZurn Elkay Water Solutions Corporation COM | 0.45% | 0.42% | 0.42% |
 EATBrinker International, Inc. COM | 0.42% | 0.53% | 0.42% |
 PTGXProtagonist Therapeutics Inc COM | 0.41% | 0.48% | 0.41% |
 GKOSGlaukos Corp. COM | 0.40% | 0.55% | 0.40% |
 SNEXStoneX Group Inc COM | 0.40% | 0.39% | 0.39% |
 RHPRyman Hospitality Properties Inc COM | 0.38% | 0.43% | 0.38% |
 FORMFormfactor Inc COM | 0.38% | 0.49% | 0.38% |
 PLXSPlexus Corp COM | 0.34% | 0.39% | 0.34% |
 TGTXTG Therapeutics Inc COM | 0.32% | 0.36% | 0.32% |
 POWLPowell Industries Inc. COM | 0.35% | 0.32% | 0.32% |
 AROCArchrock Inc COM | 0.40% | 0.32% | 0.32% |
 BCPCBalchem Corp COM | 0.37% | 0.32% | 0.32% |
 CWSTCasella Waste Systems, Inc., Class A | 0.34% | 0.31% | 0.31% |
 LUMNLumen Technologies Inc COM | 0.39% | 0.31% | 0.31% |
 KGSKodiak Gas Services Inc. COM | 0.33% | 0.30% | 0.30% |
 IBPInstalled Building Products Inc COM | 0.41% | 0.30% | 0.30% |
 PTCTPTC Therapeutics, Inc. COM | 0.29% | 0.32% | 0.29% |
 GVAGranite Construction Inc COM | 0.30% | 0.29% | 0.29% |
 ALKSAlkermes PLC COM USD0.01 | 0.29% | 0.44% | 0.29% |
 VSECVSE Corp. COM | 0.29% | 0.35% | 0.29% |
 ACIWACI Worldwide Inc COM | 0.28% | 0.31% | 0.28% |
 MYRGMYR Group, Inc. | 0.29% | 0.28% | 0.28% |
Showing the top 250 of 297 shared holdings by overlap weight.
Frequently Asked Questions
How much do IWO and SPSM overlap?
IWO and SPSM overlap by 35.7% of portfolio weight. They share 297 holdings (IWO holds 1101 positions and SPSM holds 604), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWO and SPSM?
The two portfolios are 35.7% 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 SPSM?
The largest positions held by both funds are ESE, AGX, FSS, ZWS and EAT. Together the top 10 shared positions account for 12% of the total overlap.
What does IWO own that SPSM doesn't?
804 positions (60.8% of IWO) are unique to IWO, led by BE, FN and CRDO. In the other direction, 307 positions (48.9% of SPSM) are unique to SPSM.