Aon vs Marsh McLennan
Marsh McLennan reported revenue of $27.0 billion in fiscal 2025, 1.6 times Aon's $17.2 billion in fiscal 2025. Aon's revenue grew 9.4% in its latest year, and Marsh McLennan's grew 10.3%. Aon had an operating margin of 25.3%, against 23.1% at Marsh McLennan. Free cash flow was $3.2 billion at Aon and $5.0 billion at Marsh McLennan.
Side by side
| Aon | Marsh McLennan | |
|---|---|---|
| Latest fiscal year | FY2025, Dec 31, 2025 | FY2025, Dec 31, 2025 |
| Revenue | $17.2B | $27.0B |
| Revenue growth | 9.4% | 10.3% |
| Revenue growth a year, last 5 years | 9.2% | 9.4% |
| Gross margin | — | — |
| Operating margin | 25.3% | 23.1% |
| Net margin | 21.5% | 15.4% |
| Free cash flow | $3.2B | $5.0B |
| Free cash flow margin | 18.7% | 18.5% |
| Return on capital | 15.6% | 15.0% |
| Net debt to EBITDA | 2.8x | 2.6x |
| Dividends and buybacks | $1.6B | $3.7B |
| Change in diluted share count | 2.2% | −0.4% |
| Last close | $302.06 | $194.72 |
| P/E at the last close | 16.7× | 23.3× |
| Insider trades, last 12 months | bought $7.8 million, sold $7.8 million | sold $20.0 million |
| Piotroski F-score | 4 of 8 | 5 of 8 |
Amounts in each company's own currency, US$ unless marked (a foreign company may report in another), each company's latest fiscal year from its 10-K, or 20-F or 40-F for a foreign company. Growth rates compare with the year before; the five-year rate is the average a year. Free cash flow is cash from operations minus capital spending; return on capital is after-tax operating income over the money invested in the business; P/E is the last close over the latest earnings per share. Banks are measured differently (return on equity, efficiency ratio), so some rows apply to one company only.
Ten years
Revenue
US$ billions, fiscal years
AonMarsh McLennan
Operating margin
Percent of revenue
AonMarsh McLennan
Free cash flow
US$ billions. Cash from operations minus capital expenditure.
AonMarsh McLennan
Source: the companies' Form 10-K filings, from SEC EDGAR, and the last close. For information only, not investment advice: the figures describe results, not which company is the better investment. The Filing Desk is not affiliated with either company. Full figures on the Aon and Marsh McLennan pages.