Aon Plc vs Marsh

Aon Plc (AON) is overvalued and Marsh (MRSH) is overvalued.

Both trade above our estimate of their intrinsic value. AON is the closer of the two: -56%, against -75% for MRSH.

Values as of the 22 Sept 2026 close.

Aon Plc (AON)

Book value at 2.50x, the multiple a 44.9% return on equity justifies, blended with earnings, values the shares at $183.57; the price of $286.10 is 56% above that value.

Leak Score 59/100 on 3 of 12 signals

Marsh (MRSH)

Book value at 2.50x, the multiple a 25.7% return on equity justifies, blended with earnings, values the shares at $96.90; the price of $170.01 is 75% above that value.

Leak Score 48/100 on 10 of 12 signals

MetricAONMRSH
VerdictOvervaluedOvervalued
Price$286.10$170.01
Intrinsic value$183.57$96.90
Margin of safety-56%-75%
Leak Score59/100 (3/12)48/100 (10/12)
Market cap$60.7B$81.1B
Revenue growth, 5 years9.3%9.4%
Operating margin28.5%24.3%
Net margin22.3%14.2%
Return on equity44.9%25.7%
Debt to equity1.651.47
P/E15.8x20.8x
Forward P/E13.9x14.9x
P/B6.3x5.3x
Dividend yield1.1%2.2%

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