MRSH vs SPY: Correlation
Measured on weekly returns over the past three years, Marsh McLennan (MRSH) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.26, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MRSH and SPY?
On 3 years of weekly data the MRSH/SPY correlation comes out at 0.26, weak. The link has loosened recently: the 1-year correlation (0.04) runs below the 3-year figure (0.26). The 5-year figure is 0.52, and annualized covariance runs at 68.1 %².
By 3-year correlation, SPY places #23 of the 38 assets tracked against MRSH. Their recent paths diverged sharply: over the last 12 months SPY outperformed by 26.6 percentage points (-6.0% for MRSH against +20.6% for SPY). Do not treat this figure as fixed: across three years the rolling one-year correlation ranged all the way from 0.01 to 0.73.
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.
MRSH vs SPY: side by side
| MRSH (Marsh McLennan) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -6.0% | +20.6% |
| 5-year return | +31.3% | +82.4% |
| Volatility (ann.) | 18.1% | 14.5% |
| Beta vs S&P 500 | 0.33 | 1.00 |
| Max drawdown (3Y) | -34.4% | -18.8% |
| Market cap | $90.7B | – |
| P/E (trailing) | 23.6 | – |
| Dividend yield | 1.91% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | Financials | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | MRSH | SPY |
|---|---|---|
| 2022 | -3.5% | -18.2% |
| 2023 | +16.1% | +26.2% |
| 2024 | +13.7% | +24.9% |
| 2025 | -11.3% | +17.7% |
| 2026 | +4.0% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
MRSH represents 0.14% of SPY's portfolio, so part of any move in SPY is MRSH itself, and the correlation between them is partly mechanical.
Are MRSH and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.26 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between MRSH and SPY?
As of 2026-08-27, the correlation of weekly returns between MRSH and SPY is 0.26 over 3 years, 0.04 over 1 year and 0.52 over 5 years.
Is SPY a good diversifier for MRSH?
Yes, to a useful degree: a correlation of 0.26 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.26 mean?
A reading of 0.26 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: MRSH correlations · SPY correlations
