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MMC
Marsh McLennan Companies, Inc. · Financials - Insurance Brokerage & Risk Consulting
$171.94
-1.22% this month
VERSUS
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COMPARE
AON
Aon plc · Financials - Insurance Brokerage & Risk Consulting
$317.74
-1.83% this month
Scoreboard verdict
Across AI score, momentum, valuation, upside, operating margin
MMC
1
AON
4
Comparison scoreboard
AON LEADS 4/5AI Score
MMC 49.6
AON ✓50.0
1Y Return
MMC -25.93%
AON ✓-9.43%
Fwd P/E
MMC 17.72
AON ✓15.65
Target Up.
MMC ✓+15.33%
AON +14.55%
Op. Margin
MMC 19.24%
AON ✓35.84%
Metrics last refreshed: 6/20/2026
Quick take
MMC vs AON Stock Comparison: AI Score, Valuation, Performance and Upside
MMC (Marsh McLennan) and AON (Aon plc) are the world's two largest insurance brokerage and risk consulting firms with very similar business models, client bases, and competitive positions — both generate recurring commission and fee revenue from commercial insurance placement, reinsurance brokerage, and employee benefits consulting. The primary differences are MMC's larger scale, Oliver Wyman strategic consulting division, and organic growth track record versus Aon's Business Services platform investment and 3x3 growth strategy.
MMC vs AON is the world's largest insurance broker with diversified consulting (Marsh McLennan's Marsh brokerage, Guy Carpenter reinsurance, Mercer HR consulting, and Oliver Wyman strategy consulting providing revenue diversification across insurance and consulting cycles) versus the second-largest insurance broker executing platform standardization strategy (Aon's Commercial Risk, Reinsurance, Health, and Wealth Solutions businesses investing in the Aon Business Services shared platform for margin improvement and data analytics differentiation) — both high-quality brokerage businesses competing primarily on execution and capital allocation.
Live analysis · updated 6/20/2026
AON holds the edge across 4 of 5 key metrics in this comparison. AON leads on both 1-year return (-9.43%) and forward P/E (15.65x vs 17.72x for MMC), a relatively favorable combination of momentum and valuation. On fundamentals, MMC is growing revenue faster (11.50%), while AON maintains the higher operating margin (35.84%) — a classic growth-versus-profitability split. Analyst consensus implies similar upside for both: +15.33% for MMC and +14.55% for AON.
Normalized 1Y performance
MMC
AON
Recent returns
MMC
AON
Analyst price targets & sentiment
MMC
Price target range
analyst mean$210.71
current price$171.94
+15.3% upside to analyst mean
AON · 19 analysts
STRONG BUYHOLDSTRONG SELL
Buy (2.4/5.0)
Price target range
analyst low$332.65
analyst high$449.00
analyst mean$384.11
current price$317.74
+14.6% upside to analyst mean
Who should consider this stock?
MMC may suit investors who:
- →Value Marsh McLennan's top-line scale advantage as the world's largest insurance broker — Marsh's premium placement volume provides superior carrier access and negotiating leverage that compounds into better client service
- →Appreciate MMC's four-segment diversification across Marsh insurance brokerage, Guy Carpenter reinsurance, Mercer HR consulting, and Oliver Wyman strategy consulting as reducing single-cycle dependency
- →Prefer MMC's consistent organic revenue growth track record versus Aon's more recent execution challenges post-WTW merger attempt
AON may suit investors who:
- →Believe Aon's Business Services platform investment will generate superior operating margin improvement over the medium term, creating better earnings growth from the same revenue base
- →Value Aon's 3x3 strategy commitments (specific financial targets across three years) as providing management accountability and investor clarity on capital allocation priorities
- →See Aon's lower current valuation multiple versus MMC as an opportunity if Aon can demonstrate re-accelerating organic growth execution
Performance & AI score
| Metric | MMC | AON |
|---|---|---|
| AI score | 49.6 | 50.0 |
| AI rank | #496 | #471 |
| Latest close | $171.94 | $317.74 |
| 1M return | -1.22% | -1.83% |
| 6M return | -13.21% | -9.74% |
| 1Y return | -25.93% | -9.43% |
$10,000 invested — hypothetical growth (dividends reinvested)
How much would $10,000 be worth today if invested at the start of each period, with all dividends reinvested?
| Period | MMC | AON |
|---|---|---|
| 1Y ago | $7.46K (-25.4%) started 2025-03-18 | $9.06K (-9.4%) started 2025-06-18 |
| 5Y ago | $16.3K (+63.0%) started 2021-03-18 | $14.34K (+43.4%) started 2021-06-21 |
| 10Y ago | $39.62K (+296.2%) started 2016-03-18 | $34.88K (+248.8%) started 2016-06-20 |
Hypothetical — past performance does not guarantee future results.
Valuation & upside potential
| Metric | MMC | AON |
|---|---|---|
| Market cap | $89.82B | $71.61B |
| Trailing P/E | 21.93 | 18.41 |
| Forward P/E | 17.72 | 15.65 |
| Price/Sales | N/A | 4.90 |
| EV/Revenue | 4.11 | 4.92 |
| Analyst target | $210.71 | $384.11 |
| Target upside | +15.33% | +14.55% |
Growth, profitability & risk
| Metric | MMC | AON |
|---|---|---|
| Revenue growth | 11.50% | 6.50% |
| Earnings growth | 0.00% | 27.10% |
| EPS growth | 0.00% | +27.10% |
| FCF margin | +17.85% | +19.11% |
| Operating margin | 19.24% | 35.84% |
| Profit margin | 15.60% | 22.54% |
| ROIC proxy | 28.73% | 46.45% |
| Return on equity | 28.73% | 46.45% |
| Dividend yield | 1.97% | 0.98% |
| Beta | 0.75 | 0.71 |
| Debt/equity | 139.50 | 155.05 |
| Current ratio | 1.12 | 1.07 |
| Quick ratio | 0.52 | 0.26 |
Drawdown & downside risk
Lower drawdown and smaller single-period drops generally indicate a smoother ride, though they do not guarantee lower future risk.
1Y risk snapshot
MMC max drawdown30.04%
AON max drawdown17.85%
MMC max wkly drop9.48%
AON max wkly drop11.49%
5Y risk snapshot
MMC max drawdown30.04%
AON max drawdown25.38%
MMC max wkly drop9.48%
AON max wkly drop12.29%
10Y risk snapshot
MMC max drawdown35.80%
AON max drawdown38.73%
MMC max wkly drop19.03%
AON max wkly drop19.97%
Performance metrics by period
| Period | Metric | MMC | AON |
|---|---|---|---|
| 1Y | Growth | -25.69% | -9.43% |
| CAGR | -25.74% | -9.44% | |
| Sharpe ratio | -1.38 | -0.49 | |
| Max drawdown | 30.04% | 17.85% | |
| Max daily drop | 8.52% | 9.27% | |
| Max wkly drop | 9.48% | 11.49% | |
| 5Y | Growth | +53.13% | +39.49% |
| CAGR | +8.90% | +6.89% | |
| Sharpe ratio | 0.31 | 0.21 | |
| Max drawdown | 30.04% | 25.38% | |
| Max daily drop | 8.52% | 9.28% | |
| Max wkly drop | 9.48% | 12.29% | |
| 10Y | Growth | +235.53% | +220.75% |
| CAGR | +12.87% | +12.37% | |
| Sharpe ratio | 0.48 | 0.42 | |
| Max drawdown | 35.80% | 38.73% | |
| Max daily drop | 12.07% | 16.70% | |
| Max wkly drop | 19.03% | 19.97% |
Business comparison
| Category | MMC | AON |
|---|---|---|
| Company | Marsh McLennan Companies, Inc. | Aon plc |
| Sector | Financial Services | Financial Services |
| Industry | N/A | Insurance Brokers |
| Core business | Marsh McLennan is the world's largest insurance brokerage and risk consulting firm by revenue, operating four primary segments: Marsh (commercial insurance brokerage — the world's largest insurance broker, placing billions of premiums annually for corporate clients), Guy Carpenter (reinsurance brokerage — placing reinsurance for insurance companies), Mercer (human resources consulting — employee benefits consulting, investment management consulting), and Oliver Wyman (strategy and economic consulting). MMC serves corporate clients from small businesses to Fortune 500 companies, insurance companies, governments, and institutional investors globally. | Aon is the world's second-largest insurance brokerage and risk consulting firm, with two primary business segments: Commercial Risk Solutions (insurance brokerage placing commercial property, casualty, and specialty insurance for corporate clients worldwide), Reinsurance Solutions (reinsurance brokerage), Health Solutions (employee benefits consulting and insurance brokerage for health plans), and Wealth Solutions (retirement consulting and investment management). Aon completed a major restructuring (Aon 3x3 strategy) simplifying its business model after the failed attempt to acquire Willis Towers Watson (blocked by the DOJ in 2021). Aon is incorporated in Ireland with operations globally. |
| Investor focus | Investors track MMC's organic revenue growth (particularly Marsh insurance brokerage, which correlates with insurance premium cycles), Mercer's consulting and investment revenue, Guy Carpenter's reinsurance brokerage revenue, operating margin expansion, and EPS growth driven by the brokerage model's recurring revenue and operating leverage. | Investors track Aon's organic revenue growth across its business segments, the 3x3 growth strategy execution (three financial commitments across three years), operating margin expansion through the Aon Business Services platform (shared services and technology standardization), and EPS growth from the brokerage model's recurring characteristics. |
MMC strengths
- →Marsh is the world's largest insurance broker with unmatched market access and negotiating leverage — placing tens of billions in premiums annually gives Marsh superior access to insurance market capacity and the ability to negotiate terms for clients that smaller brokers cannot match
- →Insurance brokerage revenue grows with insurance premium cycles — commercial insurance premiums have been in a prolonged hard market (rising premiums) driven by natural catastrophes, inflation, and capacity constraints; brokerage commissions grow as premiums rise
- →Diversified revenue from Mercer (HR consulting, investment consulting) and Oliver Wyman (strategic consulting) reduces dependence on insurance cycle — Mercer's benefits and investment consulting provides a relatively steady revenue stream independent of insurance market cycles
AON strengths
- →Aon Business Services standardization platform is creating operational leverage — Aon's investment in standardizing and automating its global operating platform is reducing operating costs and improving data analytics capabilities that strengthen client relationships
- →Reinsurance solutions business benefits from rising reinsurance pricing — reinsurance premiums have hardened significantly following major catastrophe losses (hurricanes Ian, Helene); Guy Carpenter (MMC) and Aon Reinsurance both benefit from rising reinsurance prices
- →Strong free cash flow generation and disciplined capital allocation — insurance brokerage generates strong recurring cash flow; Aon has consistently returned capital to shareholders through buybacks and dividends while investing organically in technology and platform
Risks to watch — MMC
- →Fee-based transition from commission-based brokerage creates near-term revenue pressure — regulators and large clients have pushed for fee transparency in insurance brokerage, potentially reducing brokerage commissions over time
- →Talent competition in consulting is intense — both MMC's consulting segments (Mercer, Oliver Wyman) rely on high-quality consultants; talent competition from McKinsey, BCG, Bain, Deloitte, and other consulting firms drives compensation costs
- →Economic sensitivity in consulting segments — Oliver Wyman's strategy consulting and Mercer's investment consulting are more economically sensitive than Marsh's brokerage; economic downturns reduce corporate consulting budgets
Risks to watch — AON
- →Aon's failed Willis Towers Watson merger attempt cost approximately $1B in break-up fees and management distraction — the DOJ-blocked merger created operational distraction and financial cost; Aon has recovered but the episode consumed significant management attention and capital
- →Revenue growth has been below the brokerage peer group in recent years — after the WTW merger distraction, Aon's organic growth has tracked below MMC; investors have watched Aon's 3x3 strategy execution closely to see if growth re-acceleration materializes
- →Regulatory and geopolitical exposure as a global firm — Aon operates in over 120 countries; regulatory changes (brokerage compensation transparency rules), sanctions (Russia operations affected by Ukraine war sanctions), and currency fluctuations affect consolidated results
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