Aon — Business Overview
What does Aon do?
Aon is a global professional services firm that helps organizations manage risk and their workforces. With roughly 60,000 employees operating in more than 120 countries, Aon acts primarily as an intermediary — connecting clients (corporations, insurers, pension funds, and others) with insurance, reinsurance, and benefits solutions. It earns fees and commissions for that expertise rather than taking on insurance risk itself, making it a capital-light business.
Aon reports through two segments:
| Segment | What it does | 2025 Revenue |
|---|---|---|
| Risk Capital | Insurance and reinsurance brokerage, risk consulting, captive management, and capital markets for insurers | $11,290 million |
| Human Capital | Employee benefits consulting and brokerage, retirement and pension consulting, investment advisory, and HR/talent advisory | $5,907 million |
Within Risk Capital, Commercial Risk Solutions covers the traditional insurance brokerage side (property, casualty, cyber, construction, climate, etc.), while Reinsurance Solutions helps insurance companies themselves manage their own risk by placing reinsurance and offering strategic analytics tools.
How does Aon make money?
Aon earns commissions and fees as a middleman between clients and insurers or reinsurers — it does not underwrite insurance itself. Revenue comes from three main sources: (1) commissions tied to the insurance premiums it places on behalf of clients, (2) fees paid by insurers and reinsurers for consulting, analytics, and administrative services, and (3) advisory and consulting fees paid directly by clients. The mix of these varies by business line, but the model is recurring by nature — clients renew insurance programs and benefits arrangements annually, which creates stable, repeating revenue.
Aon also earns interest income on funds it temporarily holds on behalf of clients. When collecting premiums from clients before passing them to insurers, Aon holds those funds in interest-bearing trust accounts. The principal belongs to clients and cannot be used for general operations, but the interest earned is a meaningful supplemental revenue stream.
Revenue skews toward the first and fourth quarters of each year due to seasonal buying patterns in insurance and benefits markets.
What market does Aon operate in?
Aon operates in the global insurance brokerage and HR consulting markets, both of which are large and generally growing. Insurance brokerage is driven by the volume and complexity of risk that businesses face — cyber threats, climate volatility, supply chain disruptions, and regulatory changes all push companies to spend more on risk management. These are structural tailwinds, not cyclical ones.
The reinsurance and risk analytics market is also expanding as insurers themselves need more sophisticated tools. Growing catastrophe losses (from extreme weather and other events) push insurance carriers to seek more reinsurance protection and better modeling, which benefits Aon's Reinsurance Solutions business. The company has leaned into this with proprietary analytics tools like ReMetrica and Capital Insights Explorer.
On the Human Capital side, rising healthcare costs, workforce complexity, and pension liability management keep demand for benefits and retirement consulting steady. Multinational corporations especially need help navigating different regulatory environments across 120-plus countries, which is a niche Aon explicitly serves.
Who are Aon's main competitors?
The insurance brokerage and risk consulting industry is competitive but dominated by a handful of large global players. Aon's primary competitors include Marsh McLennan, Willis Towers Watson, and Arthur J. Gallagher & Company, as well as privately held Lockton Companies. Beyond traditional brokers, Aon also competes with insurers that sell directly without brokers, large financial institutions, and consulting firms affiliated with accounting or technology companies.
Aon's competitive claims center on its global scale, proprietary data and analytics, and integrated delivery model. The firm emphasizes that its "Aon United" strategy allows it to bring Risk Capital and Human Capital solutions together for clients — a bundled, cross-selling approach that smaller regional brokers cannot easily replicate. Its global broking centers in London, Bermuda, and Singapore, along with proprietary facilities like the Aon Client Treaty, are cited as specific advantages in accessing capital markets for clients.
No single client represents more than 1% of total revenue, which suggests a highly diversified client base — a sign of limited customer concentration risk and evidence that no competitor has locked Aon out of meaningful market segments.
Where does Aon operate?
Aon has a genuinely global footprint, operating in more than 120 countries with approximately 60,000 employees worldwide. The filing does not break out revenue by specific country or region, but the company's global broking centers in London, Bermuda, and Singapore signal the importance of international markets — particularly for large, complex insurance and reinsurance placements. The UK regulator (the FCA, or Financial Conduct Authority) is specifically named alongside US federal and state agencies as a primary oversight body, indicating that the UK is a significant operating base.
Heavy regulatory obligations span many jurisdictions, which creates both complexity and a barrier to entry for smaller competitors. Aon must hold licenses in each country where it operates, comply with local rules on how client funds are held, and satisfy securities regulators (like the SEC and FINRA in the US, and equivalent bodies elsewhere) for its investment-related services. This regulatory web is a meaningful operational challenge but also discourages new entrants.