IJR vs IWM: how much do they really overlap?
IJR (iShares Core S&P Small-Cap ETF, tracking the S&P SmallCap 600) and IWM (iShares Russell 2000 ETF, tracking the Russell 2000) overlap by roughly 40% by weight. 7 of IJR's top 10 holdings also appear in IWM. A 50/50 blend of the two behaves like about 1730 equally-weighted bets (diversification grade A). In short, the two funds share a meaningful core of the same megacaps, but each also brings real exposure the other lacks.
The same companies, in both funds
These 20 holdings appear in both IJR and IWM. The weight columns show how much of each fund each name represents.
| Holding | in IJR | in IWM |
|---|---|---|
| XTSLA BLK CSH FND TREASURY SL AGENCY | 2.12% | 0.46% |
| VSAT VIASAT INC | 0.59% | 0.32% |
| GKOS GLAUKOS CORP | 0.55% | 0.31% |
| EAT BRINKER INTERNATIONAL INC | 0.50% | 0.29% |
| RHP RYMAN HOSPITALITY PROPERTIES REIT | 0.47% | 0.27% |
| PTGX PROTAGONIST THERAPEUTICS INC | 0.47% | 0.27% |
| ALKS ALKERMES | 0.46% | 0.27% |
| SNEX STONEX GROUP INC | 0.46% | 0.27% |
| AGX ARGAN INC | 0.45% | 0.26% |
| ESE ESCO TECHNOLOGIES INC | 0.45% | 0.26% |
| TRNO TERRENO REALTY REIT CORP | 0.43% | 0.25% |
| SM SM ENERGY | 0.40% | 0.25% |
| TGTX TG THERAPEUTICS INC | 0.39% | 0.25% |
| FSS FEDERAL SIGNAL CORP | 0.42% | 0.24% |
| ZWS ZURN ELKAY WATER SOLUTIONS CORP | 0.41% | 0.24% |
+ 5 more shared holdings.
Only in IJR
iShares Core S&P Small-Cap ETF — US small-cap. Its biggest holdings that IWM doesn’t have:
| CORT CORCEPT THERAPEUTICS INC | 0.63% |
| MTCH MATCH GROUP INC | 0.51% |
| KMX CARMAX INC | 0.46% |
| FORM FORMFACTOR INC | 0.46% |
| ESI ELEMENT SOLUTIONS INC | 0.45% |
| EMN EASTMAN CHEMICAL | 0.44% |
| ETSY ETSY INC | 0.44% |
| RAL RALLIANT CORP | 0.42% |
Only in IWM
iShares Russell 2000 ETF — US small-cap. Its biggest holdings that IJR doesn’t have:
| MOGA MOOG INC CLASS A | 0.39% |
| BTSG BRIGHTSPRING HEALTH SERVICES INC | 0.38% |
| HUT HUT CORP | 0.36% |
| UMBF UMB FINANCIAL CORP | 0.35% |
| CYTK CYTOKINETICS INC | 0.34% |
| KRYS KRYSTAL BIOTECH INC | 0.31% |
| CTRE CARETRUST REIT INC | 0.30% |
| ONB OLD NATIONAL BANCORP | 0.30% |
So — partly overlapping. Should you hold both?
IJR and IWM share a meaningful core of the same megacaps, but each also brings real exposure the other lacks. Held together they keep a shared megacap core but each still pulls in exposure the other lacks, so a 50/50 blend spreads to ~1730 effective positions (grade A).
Holdings as of — IJR: Jul 30, 2026 (iShares (BlackRock)); IWM: Jul 30, 2026 (iShares (BlackRock)). Refreshed monthly. Overlap is measured across each fund’s largest holdings (top 50); the diffuse long tail barely moves the math.
See this for YOUR whole portfolio, free →IJR vs IWM — FAQ
- How much do IJR and IWM overlap?
- IJR and IWM overlap by approximately 40% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 7 of IJR's 10 largest holdings are also held by IWM. They share 20 of their listed top holdings in total.
- Is it redundant to hold both IJR and IWM?
- Because they share a meaningful core of the same megacaps, but each also brings real exposure the other lacks, holding both is partly redundant: you double up on a shared core (XTSLA) while each fund still adds distinct exposure. A 50/50 blend has an effective 1730 positions and a A diversification grade.
- What does IWM hold that IJR doesn't?
- IWM's largest holdings that IJR doesn't hold include MOGA, BTSG, HUT, UMBF, CYTK. Its category is US small-cap, versus IJR's US small-cap.
- Which is more concentrated, IJR or IWM?
- IJR's top 10 holdings are 30% of its listed weight; IWM's are 26%. The more concentrated fund leans harder on its largest names.