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 44% by weight. 6 of IJR's top 10 holdings also appear in IWM. A 50/50 blend of the two behaves like about 1752 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 22 holdings appear in both IJR and IWM. The weight columns show how much of each fund each name represents.
| Holding | in IJR | in IWM |
|---|---|---|
| VSAT VIASAT INC | 0.66% | 0.35% |
| BTSG BRIGHTSPRING HEALTH SERVICES INC | 0.60% | 0.35% |
| AGX ARGAN INC | 0.60% | 0.34% |
| MXL MAXLINEAR INC | 0.58% | 0.34% |
| KRYS KRYSTAL BIOTECH INC | 0.53% | 0.30% |
| ESE ESCO TECHNOLOGIES INC | 0.49% | 0.29% |
| ALKS ALKERMES | 0.47% | 0.27% |
| SNEX STONEX GROUP INC | 0.46% | 0.27% |
| GKOS GLAUKOS CORP | 0.44% | 0.25% |
| RHP RYMAN HOSPITALITY PROPERTIES REIT | 0.44% | 0.25% |
| PLXS PLEXUS CORP | 0.44% | 0.25% |
| NPO ENPRO INC | 0.43% | 0.25% |
| TGTX TG THERAPEUTICS INC | 0.39% | 0.25% |
| FSS FEDERAL SIGNAL CORP | 0.42% | 0.24% |
| MYRG MYR GROUP INC | 0.42% | 0.24% |
+ 7 more shared holdings.
Only in IJR
iShares Core S&P Small-Cap ETF — US small-cap. Its biggest holdings that IWM doesn’t have:
| XTSLA BLK CSH FND TREASURY SL AGENCY | 1.96% |
| FORM FORMFACTOR INC | 0.67% |
| MOH MOLINA HEALTHCARE INC | 0.65% |
| ESI ELEMENT SOLUTIONS INC | 0.59% |
| MTCH MATCH GROUP INC | 0.48% |
| ECG EVERUS CONSTRUCTION GROUP INC | 0.46% |
| CORT CORCEPT THERAPEUTICS INC | 0.45% |
| RAL RALLIANT CORP | 0.45% |
Only in IWM
iShares Russell 2000 ETF — US small-cap. Its biggest holdings that IJR doesn’t have:
| MOGA MOOG INC CLASS A | 0.38% |
| HUT HUT CORP | 0.37% |
| CYTK CYTOKINETICS INC | 0.35% |
| UMBF UMB FINANCIAL CORP | 0.33% |
| FROG JFROG LTD | 0.31% |
| RIOT RIOT PLATFORMS INC | 0.30% |
| CTRE CARETRUST REIT INC | 0.28% |
| ONB OLD NATIONAL BANCORP | 0.28% |
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 ~1752 effective positions (grade A).
Holdings as of — IJR: Jun 30, 2026 (iShares (BlackRock)); IWM: Jun 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 44% measured by portfolio weight — that is the share of the smaller fund's holdings (by weight) that also sit inside the other. 6 of IJR's 10 largest holdings are also held by IWM. They share 22 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 (VSAT) while each fund still adds distinct exposure. A 50/50 blend has an effective 1752 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, HUT, CYTK, UMBF, FROG. 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 31% of its listed weight; IWM's are 26%. The more concentrated fund leans harder on its largest names.