ACWI vs IWM: Correlation & Overlap
How closely do iShares MSCI ACWI ETF (ACWI) and iShares Russell 2000 ETF (IWM) trade together? Their weekly returns over three years give a correlation of 0.81, which is very strong. By holdings, the two funds overlap 0.8% by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ACWI and IWM?
Across a 3-year window, the weekly returns of ACWI and IWM correlate at 0.81, very strong, meaning they move nearly in lockstep. The relationship has been stable: the 1-year correlation (0.80) sits close to the 3-year figure. Stretching to 5 years gives 0.85, with an annualized covariance of 219.9 %².
By 3-year correlation, IWM places #42 of the 119 assets tracked against ACWI. On 12-month performance IWM holds a 5.7-point edge, +22.7% against +28.4%. Stability stands out here, with the rolling one-year correlation confined to 0.69 through 0.88.
How is this computed?
Pearson correlation on weekly returns: ρ(A,B) = cov(rA, rB) / (σA · σB), over windows of 52, 156 and 260 weeks. Covariance is annualized (×52) and expressed in %². Full definitions on the methodology page.
ACWI vs IWM: side by side
| ACWI (iShares MSCI ACWI ETF) | IWM (iShares Russell 2000 ETF) | |
|---|---|---|
| 1-year return | +22.7% | +28.4% |
| 5-year return | +69.0% | +41.5% |
| Volatility (ann.) | 13.8% | 19.8% |
| Beta vs S&P 500 | 0.92 | 1.06 |
| Max drawdown (3Y) | -16.5% | -27.5% |
| Dividend yield | 1.44% | 0.91% |
| Expense ratio | 0.32% | 0.19% |
| Assets under management | $32.5B | $80.1B |
| Sector / category | ETF · Global | ETF · US Small & Mid Cap |
ACWI is a Global Large-Stock Blend fund from iShares: $32.5B under management, 1590 holdings, a 0.32% expense ratio, a 1.44% trailing dividend yield. IWM, iShares's Small Blend fund, carries $80.1B under management, 1757 holdings, a 0.19% expense ratio, a 0.91% trailing dividend yield.
Portfolio overlap between ACWI and IWM
The two portfolios are largely distinct. Weighing the shared positions, 0.8% of the two funds is identical, spread across 29 common holdings. That shared book is a large part of why the returns line up.
| Common holding | Weight in ACWI | Weight in IWM |
|---|---|---|
| AIR | 0.14% | 0.17% |
| MC | 0.12% | 0.12% |
| NG | 0.07% | 0.10% |
| CNR | 0.06% | 0.16% |
| AI | 0.12% | 0.04% |
| ENR | 0.13% | 0.04% |
| CCO | 0.04% | 0.03% |
| ORA | 0.03% | 0.20% |
| UCB | 0.03% | 0.13% |
| MTX | 0.02% | 0.07% |
| VAL | 0.02% | 0.15% |
| TRN | 0.02% | 0.07% |
| ACA | 0.02% | 0.23% |
| NN | 0.02% | 0.05% |
| SGP | 0.01% | 0.01% |
Largest positions held only by ACWI: NVDA (4.64%), AAPL (4.41%), MSFT (3.35%), AMZN (2.41%), GOOGL (1.91%). Only by IWM: MOGA (0.35%), UMBF (0.34%), CYTK (0.33%), GKOS (0.33%), EAT (0.33%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26. Top 15 common positions shown.
Year-by-year returns
| Year | ACWI | IWM |
|---|---|---|
| 2022 | -18.4% | -20.5% |
| 2023 | +22.3% | +16.8% |
| 2024 | +17.4% | +11.4% |
| 2025 | +22.4% | +12.7% |
| 2026 | +14.9% | +22.3% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ACWI and IWM good diversifiers for each other?
No. With a correlation of 0.81, ACWI and IWM move nearly in lockstep, so holding both adds very little diversification.
FAQ
What is the correlation between ACWI and IWM?
The ACWI/IWM correlation stands at 0.81 on a 3-year window (1 year: 0.80, 5 years: 0.85), computed from weekly returns as of 2026-08-27.
Is IWM a good diversifier for ACWI?
No. With a correlation of 0.81, ACWI and IWM move nearly in lockstep, so holding both adds very little diversification.
How much do ACWI and IWM overlap?
0.8% by weight, across 29 common holdings, based on issuer-disclosed portfolios as of 2026-08-26.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/acwi-vs-iwm.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/acwi-vs-iwm/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: ACWI correlations · IWM correlations
