AON vs MRSH: Correlation
Aon plc (AON) and Marsh McLennan (MRSH) show a strong relationship: their 3-year correlation of weekly returns is 0.72.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are AON and MRSH?
Across a 3-year window, the weekly returns of AON and MRSH correlate at 0.72, strong. Recent behaviour matches the longer record: 0.81 over 1 year against 0.72 over 3. Stretching to 5 years gives 0.77, with an annualized covariance of 284.5 %².
MRSH is one of the assets that tracks AON most closely: it ranks #1 out of the 32 assets we track against AON. Twelve-month performance is nearly a tie, at -4.6% for AON and -6.0% for MRSH. The rolling one-year correlation moved between 0.54 and 0.84 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.
AON vs MRSH: side by side
| AON (Aon plc) | MRSH (Marsh McLennan) | |
|---|---|---|
| 1-year return | -4.6% | -6.0% |
| 5-year return | +27.0% | +31.3% |
| Volatility (ann.) | 21.7% | 18.1% |
| Beta vs S&P 500 | 0.34 | 0.33 |
| Max drawdown (3Y) | -24.2% | -34.4% |
| Market cap | $74.2B | $90.7B |
| P/E (trailing) | 19.5 | 23.6 |
| Dividend yield | 0.86% | 1.91% |
| Sector / category | Financials | Financials |
Year-by-year returns
| Year | AON | MRSH |
|---|---|---|
| 2022 | +0.6% | -3.5% |
| 2023 | -2.3% | +16.1% |
| 2024 | +24.5% | +13.7% |
| 2025 | -1.2% | -11.3% |
| 2026 | -0.5% | +4.0% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are AON and MRSH good diversifiers for each other?
To a limited degree. At 0.72 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
FAQ
What is the correlation between AON and MRSH?
The AON/MRSH correlation stands at 0.72 on a 3-year window (1 year: 0.81, 5 years: 0.77), computed from weekly returns as of 2026-08-27.
Is MRSH a good diversifier for AON?
To a limited degree. At 0.72 the two still catch most of the same waves, so the pair smooths returns a little without insulating either from a shared selloff.
What does a correlation of 0.72 mean?
A reading of 0.72 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: AON correlations · MRSH correlations
