BRO vs MMC vs AON vs AJG

For growth investors, Brown & Brown, Inc.

(BRO) is the stronger pick with 26. 6% revenue growth year-over-year, versus 7. 6% for Marsh & McLennan Companies, Inc. (MMC). Brown & Brown, Inc. (BRO) offers the better valuation at 18. 4x trailing P/E (12. 8x forward), making it the more compelling value choice. Analysts rate Aon plc (AON) a "Buy" — based on 38 analyst ratings — the highest consensus in this comparison. The "better buy" depends entirely on your goals: growth investors should weight revenue trajectory, value investors should weight P/E and PEG, and income investors should weight dividend yield and streak.

On trailing P/E, Brown & Brown, Inc.

(BRO) is the cheapest at 18. 4x versus Arthur J. Gallagher & Co. at 35. 1x. On forward P/E, Brown & Brown, Inc. is actually cheaper at 12. 8x. The PEG ratio (P/E divided by earnings growth rate) is the most growth-adjusted single valuation metric: Marsh & McLennan Companies, Inc. wins at 0. 88x versus Arthur J. Gallagher & Co. 's 2. 35x — a PEG below 1. 0 traditionally signals the market is underpricing earnings growth.

Over the past 5 years, Arthur J.

Gallagher & Co. (AJG) delivered a total return of +41. 1%, compared to +12. 8% for Brown & Brown, Inc. (BRO). Over 10 years, the gap is even starker: AJG returned +372. 4% versus MMC's +209. 8%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.

By beta (market sensitivity over 5 years), Brown & Brown, Inc.

(BRO) is the lower-risk stock at 0. 07β versus Marsh & McLennan Companies, Inc. 's 0. 14β — meaning MMC is approximately 89% more volatile than BRO relative to the S&P 500. On balance sheet safety, Arthur J. Gallagher & Co. (AJG) carries a lower debt/equity ratio of 60% versus 173% for Aon plc — giving it more financial flexibility in a downturn.

By revenue growth (latest reported year), Brown & Brown, Inc.

(BRO) is pulling ahead at 26. 6% versus 7. 6% for Marsh & McLennan Companies, Inc. (MMC). On earnings-per-share growth, the picture is similar: Aon plc grew EPS 36. 3% year-over-year, compared to -11. 9% for Arthur J. Gallagher & Co.. Over a 3-year CAGR, BRO leads at 18. 7% annualised revenue growth. Higher growth typically commands a higher valuation multiple — check whether the premium P/E or P/S is justified by the growth rate using the PEG ratio.

Aon plc (AON) is the more profitable company, earning 21.

5% net margin versus 10. 7% for Arthur J. Gallagher & Co. — meaning it keeps 21. 5% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: BRO leads at 28. 5% versus 18. 3% for AJG. At the gross margin level — before operating expenses — BRO leads at 87. 7%, reflecting greater pricing power or product mix advantage. Stronger margins indicate durable pricing power, lower cost of revenue, or higher mix of software/services. They are one of the clearest signs of business quality.

The PEG ratio (forward P/E divided by expected earnings growth rate) is the most precise measure of undervaluation relative to growth potential.

By this metric, Marsh & McLennan Companies, Inc. (MMC) is the more undervalued stock at a PEG of 0. 88x versus Arthur J. Gallagher & Co. 's 2. 35x. A PEG below 1. 0 is traditionally considered the threshold for growth-adjusted undervaluation. On forward earnings alone, Brown & Brown, Inc. (BRO) trades at 12. 8x forward P/E versus 16. 9x for Marsh & McLennan Companies, Inc. — 4. 1x cheaper on a one-year earnings basis. Analyst consensus price targets imply the most upside for BRO: 52. 4% to $88. 50.

All stocks in this comparison pay dividends.

Marsh & McLennan Companies, Inc. (MMC) offers the highest yield at 1. 8%, versus 0. 9% for Aon plc (AON).

For long-horizon retirement investors, Arthur J.

Gallagher & Co. (AJG) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (low volatility (β 0. 09), 1. 3% yield, +372. 4% 10Y return). Both have compounded well over 10 years (AJG: +372. 4%, MMC: +209. 8%), confirming both are viable long-term holds — but the lower-volatility option typically results in less emotional selling during corrections. Retirement portfolios generally favour predictability over maximum returns. Consult a financial advisor before making allocation decisions.

Both stocks operate in the Financial Services sector, making this a peer-level intra-sector comparison — the same macro tailwinds and headwinds will affect both.

In terms of investment character: BRO is a mid-cap high-growth stock; MMC is a mid-cap quality compounder stock; AON is a mid-cap quality compounder stock; AJG is a mid-cap high-growth stock. These fundamental differences mean investors should not choose between them on a single metric — the "better stock" depends entirely on which of these characteristics aligns with your investment strategy.