Marsh McLennan vs Aon: which stock is doing better?
Marsh McLennan and Aon are business rivals. Where they compete: commercial insurance and reinsurance brokerage plus HR/benefits consulting. Here is how the two stocks, and the businesses behind them, compare over the past year.
Updated Oct 9, 2026
Close call
On Stox’s P3 score, Marsh McLennan rates 29 and Aon 27, too close to call. Over the past year Marsh McLennan is −14% and Aon −25%, against +16% for the S&P 500. Marsh McLennan has grown revenue faster, +10% against +7%. By type, Marsh McLennan is a Falling Knife and Aon a Show-Me Grower.
The past year
MRSH against AON, each set to $100 a year ago. Select a measure in the table below to chart it for both.
MRSH and AON side by side
Ahead marks the stronger reading on each line; for the typical day and the deepest fall it marks the steadier stock. Select a row with a chart to see both over the year.
| Measure | MRSH | AON | Ahead |
|---|---|---|---|
P3 score Market beat, staying power and business growth combined | 29Weak | 27Weak | MRSH |
Past year Share price change | −14% | −25% | MRSH |
Past 3 months Share price change | −3% | −26% | MRSH |
Past month Share price change | −1% | −11% | MRSH |
Market beat Return against the market, past year | 22Weak | 12Weak | MRSH |
Staying power How steadily it has led, 52 weeks | 28Weak | 23Weak | MRSH |
Business growth Revenue, margins and cash flow growth | 39Middling | 72Strong | AON |
Money flow Buying against selling on volume, 60 days | 83Strong | 2Weak | MRSH |
Revenue growth Past four quarters against the year before | +10% | +7% | MRSH |
Operating margin Operating profit as a share of revenue, past four quarters | 22% | 28% | AON |
Typical day Average daily move over the past year | 2.2% | 2.4% | MRSH, calmer |
Deepest fall From a high, past year | −24% | −29% | MRSH, held up |
Market value What the market values the company at | $83.9B | $58.0B | |
Type Its Stox Atlas type | Falling Knife | Show-Me Grower | |
Group Stocks it moves with | Insurance | Insurance | Same group |
How to read this page
How it’s measured. Scores from Stox rank each stock against about 1,200 large US stocks and funds, where 100 is best; P3 combines market beat, staying power and business growth. Returns are share-price changes. The typical day is the average true range over 14 days as a share of the price, averaged over the past year.
Sources. Daily prices and company financial statements from Financial Modeling Prep; scores and curated rivals from Stox.
A higher score describes a stronger past year, not what comes next.
Rivals are chosen by the markets the two businesses compete in, not by sector labels.
For financial statements, valuation and news, see MRSH and AON on Stox.
This page is information, not investment advice. About our data and methods ›