SPY vs WTM: Correlation
How closely do SPDR S&P 500 ETF Trust (SPY) and White Mountains Insurance Group, Ltd. (WTM) trade together? Their weekly returns over three years give a correlation of 0.16, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and WTM?
On 3 years of weekly data the SPY/WTM correlation comes out at 0.16, weak. Little has changed lately, as the 1-year reading of 0.06 lands near the 3-year figure. The 5-year figure is 0.19, and annualized covariance runs at 48.9 %².
Among the 4755 assets we track against SPY, WTM ranks #3655 by 3-year correlation. The trailing year gives SPY the advantage: +20.6% versus +15.3%, a 5.3-point spread.
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.
SPY vs WTM: side by side
| SPY (SPDR S&P 500 ETF Trust) | WTM (White Mountains Insurance Group, Ltd.) | |
|---|---|---|
| 1-year return | +20.6% | +15.3% |
| 5-year return | +82.4% | +90.5% |
| Volatility (ann.) | 14.5% | 20.6% |
| Beta vs S&P 500 | 1.00 | 0.23 |
| Max drawdown (3Y) | -18.8% | -18.0% |
| Market cap | – | $5.1B |
| P/E (trailing) | – | 4.9 |
| Dividend yield | 1.01% | 0.05% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | US Listed |
On the fund side, SPY sits in the Large Blend category at State Street Investment Management, with $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | SPY | WTM |
|---|---|---|
| 2022 | -18.2% | +39.6% |
| 2023 | +26.2% | +6.5% |
| 2024 | +24.9% | +29.3% |
| 2025 | +17.7% | +6.9% |
| 2026 | +13.7% | +2.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPY and WTM good diversifiers for each other?
By historical standards, yes. A correlation of 0.16 means the two rarely move for the same reasons.
FAQ
What is the correlation between SPY and WTM?
Using weekly returns as of 2026-08-27: 0.16 over 3 years, with 0.06 over the last year and 0.19 over 5 years.
Is WTM a good diversifier for SPY?
By historical standards, yes. A correlation of 0.16 means the two rarely move for the same reasons.
What does a correlation of 0.16 mean?
A reading of 0.16 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: SPY correlations · WTM correlations
