ETF comparison
IWM vs IWO
Both US Small Cap.
Holdings overlap
1,104 positions appear in both funds. Buying equal dollars of IWM and IWO would leave roughly 70.1% of each dollar exposed to the same underlying securities.
Side by side
Sub-score comparison
Tracking quality isn't part of the composite — see what we don't score for why.
Cost difference
IWM is 5 bps cheaper than IWO. On a $100,000 position that's about $50/yr more in fees for IWO.
Fee figure is the annual expense charged on $100,000. To see how the gap compounds over a multi-decade holding period, open the cost calculator pre-filled with IWM vs IWO.
Top shared holdings
1,104 shared in total| # | Holding | In IWM | In IWO | Overlap |
|---|---|---|---|---|
| 1 | BlackRock Funds III | 14.24% | 13.68% | 13.68% |
| 2 | Bloom Energy Corp. | 1.01% | 1.99% | 1.01% |
| 3 | Coeur Mining, Inc. | 0.65% | 0.64% | 0.64% |
| 4 | Fabrinet | 0.64% | 1.26% | 0.64% |
| 5 | Nextpower, Inc. | 0.60% | 0.94% | 0.60% |
| 6 | Credo Technology Group Holding Ltd. | 0.51% | 1.02% | 0.51% |
| 7 | Kratos Defense & Security Solutions, Inc. | 0.43% | 0.86% | 0.43% |
| 8 | Advanced Energy Industries, Inc. | 0.41% | 0.82% | 0.41% |
| 9 | Sterling Infrastructure, Inc. | 0.41% | 0.81% | 0.41% |
| 10 | Bridgebio Pharma, Inc. | 0.40% | 0.79% | 0.40% |
| 11 | Guardant Health, Inc. | 0.39% | 0.77% | 0.39% |
| 12 | Modine Manufacturing Co. | 0.39% | 0.76% | 0.39% |
Only in IWM
840 total- EchoStar Corp. 0.54%
- TTM Technologies, Inc. 0.34%
- SM Energy Co. 0.26%
- Fluor Corp. 0.26%
- Vaxcyte, Inc. 0.25%
- Jackson Financial, Inc. 0.24%
- Commercial Metals Co. 0.23%
- Ormat Technologies, Inc. 0.23%
- Terreno Realty Corp. 0.21%
- Noble Corp. plc 0.21%
Only in IWO
0 totalEvery IWO position is also held by IWM.
Open IWM or IWO at a brokerage
Both funds trade commission-free at major US brokerages.
Affiliate links — opening an account through these earns PlainIndex a one-time referral. Scoring is computed before any affiliate consideration; see our methodology and funding disclosure.
Holdings overlap is the sum of min(weight_a, weight_b) over positions
matched on ISIN (CUSIP fallback). Methodology: see
/methodology/.
Comparing two funds doesn't endorse swapping one for the other. Tax-lot history, account type, and personal goals matter — PlainIndex publishes data and methodology, not investment advice.