IJR vs IWM Overlap
Both funds come from IShares. IJR is a small-cap U.S. equity ETF, while IWM is an equity ETF. IJR and IWM show meaningful overlap, with an estimated weighted overlap of 42.56%. They share 539 holdings in the loaded dataset, led by IDCC, CTRE, and MOG-A.
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Quick Answer
Both funds come from IShares. IJR is a small-cap U.S. equity ETF, while IWM is an equity ETF. IJR and IWM show meaningful overlap, with an estimated weighted overlap of 42.56%. They share 539 holdings in the loaded dataset, led by IDCC, CTRE, and MOG-A.
- 42.56% weighted overlap across 539 shared holdings.
- The top three shared holdings explain 2.17% of the measured overlap.
- IJR and IWM are closer in breadth than a broad-vs-niche ETF pair.
- The overlap is mostly explained by the top shared positions rather than sector labels alone.
- Holding both may add less diversification than the fund names imply.
Data Freshness
- IJR holdings
- Mar 12, 2026
- IWM holdings
- Mar 12, 2026
- Overlap computed
- Mar 15, 2026
- Data source
- Financial Modeling Prep
Review the methodology for the overlap formula and refresh policy.
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About These ETFs
What Stands Out In This Comparison
What This Means
Both funds come from IShares. IJR is a small-cap U.S. equity ETF, while IWM is an equity ETF. IJR and IWM overlap enough to matter, but they still bring different exposures to a portfolio. The overlap is concentrated in holdings such as IDCC, CTRE, and MOG-A, which explains why the score lands at 42.56%.
How They Differ
Both funds come from IShares. IJR is a small-cap U.S. equity ETF, while IWM is an equity ETF. Neither fund clearly dominates on breadth, so the practical difference is more about weighting, index construction, and cost. IJR has the lower expense ratio, while IWM charges more for its exposure.
What Drives The Overlap
The overlap is driven by a relatively small set of large shared positions. The top three shared holdings account for 2.17% of the score, which means the result is heavily influenced by the biggest common weights rather than a long tail of tiny positions.
When One May Fit Better
Because IJR and IWM are closer in breadth, the better fit usually comes down to index methodology, issuer preference, and cost. IJR has the lower expense ratio, while IWM charges more for its exposure.
Overlap Driver Snapshot
Concentration
The top three shared holdings explain 2.17% of the full overlap score.
That helps show whether the score comes from a handful of giant shared positions or from a broader mix of common holdings.
Shared Sector Tilt
Sector tags are not consistently available for the biggest shared positions in this dataset, so this comparison leans more on the specific holdings than on sector labels.
Top Shared Holdings
These are the holdings contributing the most to the overlap score between IJR and IWM.
| Holding | Name | IJR Wt. | IWM Wt. | Overlap |
|---|---|---|---|---|
| IDCC | INTERDIGITAL INC | 0.62% | 0.32% | 0.32% |
| CTRE | CARETRUST REIT INC | 0.59% | 0.30% | 0.30% |
| MOG-A | MOOG INC CLASS A | 0.59% | 0.30% | 0.30% |
| SITM | SITIME CORP | 0.51% | 0.26% | 0.26% |
| SMTC | SEMTECH CORP | 0.50% | 0.26% | 0.26% |
| JBTM | JBT MAREL CORP | 0.48% | 0.25% | 0.25% |
| PRIM | PRIMORIS SERVICES CORP | 0.48% | 0.24% | 0.24% |
| FORM | FORMFACTOR INC | 0.46% | 0.24% | 0.24% |
| ZWS | ZURN ELKAY WATER SOLUTIONS CORP | 0.46% | 0.24% | 0.24% |
| ESE | ESCO TECHNOLOGIES INC | 0.46% | 0.24% | 0.24% |
Why These ETFs Overlap
Both funds come from IShares. IJR is a small-cap U.S. equity ETF, while IWM is an equity ETF. The overlap exists because both funds allocate meaningful weight to the same holdings. In this dataset, the biggest shared drivers are IDCC, CTRE, and MOG-A, which appear in both portfolios and push the overlap score higher.
Holding both IJR and IWM can still be reasonable, but you should expect some duplication. The decision comes down to whether the non-overlapping parts of each ETF are important enough for your strategy.
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Frequently Asked Questions About IJR and IWM
What is the overlap between IJR and IWM?+
How many holdings do IJR and IWM share?+
Is the IJR and IWM overlap high?+
Why do IJR and IWM overlap?+
Which ETF is broader, IJR or IWM?+
How Overlap Is Calculated
A straightforward approach used by portfolio analysts.
For every stock that appears in both ETFs, we take the smaller of the two weights. Adding up all those minimums gives the total overlap percentage. A score of 100% means the two ETFs hold the exact same stocks in the same proportions.
Want the full explanation? Read the methodology page.