Arthur J. Gallagher vs Aon (AJG vs AON)
Side by side from their SEC filings: revenue, margins, growth, returns and valuation, plus short interest, insider activity and institutional ownership.
Aon is the larger company by revenue ($17.2B vs $13.9B) and market value ($76.2B vs $65.0B). Arthur J. Gallagher has grown revenue faster over the last 4 fiscal years (+69.8% cumulative vs +40.9%). Aon trades at the lower trailing P/E (19.6x vs 41.0x).
About Arthur J. Gallagher
Arthur J. Gallagher & Co. provides insurance brokerage, reinsurance brokerage, consulting, and third-party property and casualty claims settlement and administration services globally. The company serves commercial, nonprofit, public sector entities, insurance companies, and individuals through its brokerage and risk management segments. Its services include placing insurance and reinsurance coverage, managing risk and employer-sponsored benefit programs, and administering claims for self-insured entities.
About Aon
Aon plc is a global professional services firm that provides risk management, insurance brokerage, reinsurance, and human capital consulting services. Its main business segments are Risk Capital, which offers insurance and reinsurance brokerage and consulting, and Human Capital, which delivers health, benefits, talent advisory, and retirement consulting services. Aon serves clients in over 120 countries across various industries and market segments.
Head to head (AJG FY2025 vs AON FY2025)
| Metric | AJGFY2025 | AONFY2025 |
|---|---|---|
| Revenue | $13.94B | $17.18B |
| Revenue growth (YoY) | 20.7% | 9.4% |
| Gross margin | — | — |
| Operating margin | — | 25.3% |
| Net margin | 10.7% | 21.5% |
| Net income | $1.49B | $3.69B |
| Diluted EPS | $5.74 | $17.02 |
| FCF margin | — | 18.7% |
| ROE | 6.4% | 39.1% |
| Debt / equity | 0.5× | 1.5× |
| Market cap | $65.03B | $76.23B |
| P/E (TTM) | 41.0× | 19.6× |
Fundamentals are from each company’s SEC filings (AJG FY2025, AON FY2025). P/E and market cap are derived from recent market prices and update daily.
Five-year trend (as reported)
| Revenue | FY2021 | FY2022 | FY2023 | FY2024 | FY2025 |
|---|---|---|---|---|---|
| AJG | $8.21B | $8.55B | $10.07B | $11.55B | $13.94B |
| AON | $12.19B | $12.48B | $13.38B | $15.70B | $17.18B |
Peer standing
Where each company ranks among the 88 insurance companies, on the same scale. Each figure is ranked only against peers that report it. Percentiles describe position in the distribution, not a rating.
| Metric | AJG | AON |
|---|---|---|
| Net margin | 10.7%48th percentile of 82 | 21.5%83rd percentile of 82 |
| Revenue growth (YoY) | +20.7%68th percentile of 88 | +9.4%49th percentile of 88 |
| ROE | 6.4%24th percentile of 73 | 39.1%99th percentile of 73 |
| P/E (TTM) | 41.0×89th percentile of 71 | 19.6×77th percentile of 71 |
| Debt / equity | 0.52×77th percentile of 48 | 1.55×94th percentile of 48 |
| Short interest (days to cover) | 3.36d60th percentile of 86 | 1.61d13th percentile of 86 |
Short interest
| FINRA settlement data | AJG | AON |
|---|---|---|
| Shares sold short | 6.8M | 3.7M |
| Change vs prior settlement | -0.8% | +2.9% |
| Days to cover | 3.36 | 1.61 |
| As of settlement | 2026-06-30 | 2026-06-30 |
Source: FINRA Consolidated Short Interest. FINRA is the owner and source of the FINRA-supplied data; republishing or redistributing it is not permitted. Not presented as a percentage of float. No FINRA endorsement of this product is implied.
Insider activity (last 90 days)
| Form 4 open-market activity | AJG | AON |
|---|---|---|
| Buys | 0 | 0 |
| Sells | 1 ($618,000) | 1 ($216,000) |
Open-market purchases and sales reported on SEC Form 4 (grants, exercises and tax withholding excluded). For context, about 16% of covered companies saw any open-market insider buy in a 90-day window.
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Data sourced from SEC EDGAR (public domain). Figures are as-reported and may be unaudited or restated; verify against the source filings before relying on them. Comparisons are descriptive (higher or lower on a reported figure), not a rating or a recommendation. Informational only. Not investment advice.