IWM vs VOO: Correlation & Overlap
iShares Russell 2000 ETF (IWM) and Vanguard S&P 500 ETF (VOO) show a strong relationship: their 3-year correlation of weekly returns is 0.78. By holdings, the two funds overlap 0% by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IWM and VOO?
On 3 years of weekly data the IWM/VOO correlation comes out at 0.78, strong. The relationship has been stable: the 1-year correlation (0.74) sits close to the 3-year figure. The 5-year figure is 0.83, and annualized covariance runs at 221.4 %².
By 3-year correlation, VOO places #20 of the 320 assets tracked against IWM. The trailing year gives IWM the advantage: +28.4% versus +20.6%, a 7.8-point spread. The rolling one-year correlation moved between 0.61 and 0.90 over the past three years, a moderate range.
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.
IWM vs VOO: side by side
| IWM (iShares Russell 2000 ETF) | VOO (Vanguard S&P 500 ETF) | |
|---|---|---|
| 1-year return | +28.4% | +20.6% |
| 5-year return | +41.5% | +83.0% |
| Volatility (ann.) | 19.8% | 14.4% |
| Beta vs S&P 500 | 1.06 | 0.99 |
| Max drawdown (3Y) | -27.5% | -18.7% |
| Dividend yield | 0.91% | 1.07% |
| Expense ratio | 0.19% | 0.03% |
| Assets under management | $80.1B | $1,686.9B |
| Sector / category | ETF · US Small & Mid Cap | ETF · US Large Cap |
IWM, iShares's Small Blend fund, carries $80.1B under management, 1757 holdings, a 0.19% expense ratio, a 0.91% trailing dividend yield. VOO, Vanguard's Large Blend fund, carries $1,686.9B under management, 503 holdings, a 0.03% expense ratio, a 1.07% trailing dividend yield.
Portfolio overlap between IWM and VOO
The two portfolios are largely distinct. Weighing the shared positions, 0% of the two funds is identical, spread across 0 common holdings. That shared book is a large part of why the returns line up.
Largest positions held only by IWM: MOGA (0.35%), UMBF (0.34%), CYTK (0.33%), GKOS (0.33%), EAT (0.33%). Only by VOO: NVDA (7.56%), AAPL (7.05%), MSFT (5.37%), AMZN (4.13%), GOOGL (3.25%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26.
Year-by-year returns
| Year | IWM | VOO |
|---|---|---|
| 2022 | -20.5% | -18.2% |
| 2023 | +16.8% | +26.3% |
| 2024 | +11.4% | +25.0% |
| 2025 | +12.7% | +17.8% |
| 2026 | +22.3% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are IWM and VOO good diversifiers for each other?
Somewhat, no more. With 0.78 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between IWM and VOO?
As of 2026-08-27, the correlation of weekly returns between IWM and VOO is 0.78 over 3 years, 0.74 over 1 year and 0.83 over 5 years.
Is VOO a good diversifier for IWM?
Somewhat, no more. With 0.78 correlation, most large moves hit both names, and the diversification benefit stays modest.
How much do IWM and VOO overlap?
0% by weight, across 0 common holdings, based on issuer-disclosed portfolios as of 2026-08-26.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/iwm-vs-voo.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/iwm-vs-voo/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: IWM correlations · VOO correlations
