stockrowWhat it does
Aon plc is a professional services firm that helps organizations manage risk and make decisions about their employees and investments. Founded in 1982 and headquartered in London, it is led by President and Chief Executive Officer Gregory C. Case.
Its Risk Capital business helps clients arrange insurance and reinsurance—the insurance that insurers buy to transfer some of their own risks. Aon also advises organizations on retaining or transferring risks, managing claims and raising capital. Its specialists work on exposures such as property damage, cyber incidents, construction projects and professional liability.
Its Human Capital business advises employers on health benefits, compensation and workforce decisions. It also provides retirement and pension advice, pension administration and investment consulting. For some investment clients, Aon manages portfolios under delegated arrangements.
Aon serves organizations across industries and in more than 120 countries. Its clients include employers, insurers, reinsurers, investment firms, corporations, public pensions, endowments and foundations. Its work can combine advice, data analysis, technology and access to insurance or other sources of capital.
The company organizes its activities around Risk Capital and Human Capital, with a strategy of connecting expertise across the firm. In 2025, it launched a program that combines insurance for data-center projects from construction through ongoing operations. Aon also holds client premiums and claims in transit, although those funds are segregated from its own operating cash.
How it makes money
Aon earns revenue primarily from commissions, fees paid by insurance and reinsurance companies, and fees paid by clients. Brokerage compensation can depend on the premium, the coverage, the services provided and the capacity in which Aon acts. Fees for advice and consulting depend on the extent and value of the work.
In Risk Capital, Commercial Risk Solutions arranges insurance and provides risk consulting, claims advice and captive management. A captive is an insurance vehicle an organization can use as part of its approach to retaining risk. Aon also develops and administers insurance programs for sponsored groups and other distribution channels. Reinsurance Solutions helps insurers transfer risks, advises on capital and strategy, and provides modeling and capital-markets services.
In Human Capital, Health Solutions earns revenue from benefits brokerage and consulting, consumer benefits, compensation and talent advice. Wealth Solutions provides retirement consulting, pension administration and investment advice, including delegated investment management. Investment advisory clients include corporations, public pensions, endowments and foundations.
Aon focuses its portfolio on professional services with recurring revenue. It reviews clients’ losses and exposures throughout the year, while some relationships include ongoing pension administration or investment management. Revenue tends to be higher in the first and fourth quarters because of customer buying patterns and the timing of service delivery.
Aon can earn interest on certain premiums and claims held in segregated accounts, but cannot use the principal for general operations. Its consolidated revenue was $17.2 billion in 2025 and $4.1 billion in Q3 2026.
| Segment | Revenue, FY2025 | Share | Change on the year |
|---|---|---|---|
| Risk Capital | $11.3 billion | 65.7% | 7.35% |
| Human Capital | $5.9 billion | 34.3% | 13.4% |
Customers and how it sells
Aon serves clients across market segments and nearly every industry, from employers seeking benefits advice to insurers buying reinsurance. Its investment advisory clients include corporations, public pensions, endowments and foundations. The company also works with sponsored groups and other distribution channels to develop and administer customized insurance programs.
Its largest client accounted for approximately 1% of total revenue in 2025. Aon places coverage with many insurers; no single carrier accounted for more than 10% of the premiums it placed for clients that year. Aon also works with insurers and other partners to develop employee benefits solutions.
The U.S. generated $8.3 billion of revenue in 2025, or 48.2% of the total. Aon operates in more than 120 countries, with global broking centers in London, Bermuda and Singapore. Its multinational benefits work includes program design, financing and regulatory assistance across countries.
In Q3 2026, Aon became lead broker for the reinsurance program of a new Thai government natural catastrophe program. Local insurers execute the program, which covers flood, earthquake and windstorm risks for 30 million households in Thailand.
| Region | Revenue, FY2025 | Share | Change on the year |
|---|---|---|---|
| U.S. | $8.3 billion | 48.2% | 8.00% |
| Europe, Middle East, & Africa other than U.K. and Ireland | $3.2 billion | 18.4% | 8.72% |
| U.K. | $2.2 billion | 12.9% | 12.4% |
| Asia Pacific | $1.7 billion | 9.96% | 2.09% |
| Americas other than U.S. | $1.6 billion | 9.50% | 22.3% |
| Ireland | $185.0 million | 1.08% | 26.7% |
Suppliers and costs
Aon is a services business rather than a manufacturer. It relies on employees, technology and relationships with insurance carriers and other capital providers to deliver advice and arrange coverage. Its health business also partners with insurers and other organizations to develop benefits solutions. Aon had 60,000 employees at the end of 2025.
Its operating costs include compensation and benefits, information technology, office premises, depreciation, and amortization or impairment of intangible assets. Compensation and benefits rose in 2025, principally because of NFP operating expenses and expenses associated with organic growth, partly offset by restructuring savings. Technology costs cover support and maintenance of infrastructure; premises costs cover offices around the world.
Total operating expenses were $12.8 billion in 2025. They included costs from NFP and expenses associated with growth, partly offset by restructuring savings and lower NFP transaction and integration expenses. Amortization and impairment also increased, primarily because of intangible assets acquired from NFP. Aon incurred interest expense on its debt separately from operating expenses.
- Revenue$17.2B
- Cost of revenue−$9.0B
- Selling, general and administrative−$1.6B
- Other operating costs−$2.2B
- Operating income$4.3B
Competitive position
Aon operates in a competitive, fragmented market. It competes with global brokers and consulting companies including Marsh McLennan, Willis Towers Watson, Arthur J Gallagher & Company and Lockton Companies, as well as regional and local firms. Insurers and reinsurers that sell directly can bypass brokers; financial institutions and independent or affiliated consulting organizations also compete with parts of Aon’s business.
Aon combines brokerage with analytics, consulting and access to insurance and other capital. Its commercial risk teams design insurance programs and review client losses and exposures. Its reinsurance business uses modeling and advisory tools, while its human capital services address benefits, retirement and investments.
Our reading: Aon’s broad geographic reach and range of services offer a meaningful competitive advantage in serving clients with needs across countries and disciplines, although other global firms compete in many of the same areas. Our reading: Its analytics and specialist expertise can help distinguish its advice and insurance placement, but technology-enabled rivals and direct sellers limit their protection. Our reading: Ongoing client relationships support retention, though the available evidence does not establish that clients face high switching costs.
Aon said retention remained in the mid-90s in Q3 2026. In that quarter, 5,600 clients used its risk analytics.
| Competitor | Where they compete | Threat (our reading) |
|---|---|---|
| Marsh McLennan | Global insurance brokerage and consulting | High |
| Willis Towers Watson | Global insurance brokerage and consulting | High |
| Arthur J Gallagher & Company | Global insurance brokerage and consulting | High |
| Lockton Companies, Inc. | Global insurance brokerage and consulting | High |
Growth opportunities
Aon’s growth strategy combines new client wins, retention, expansion of work for existing clients and investment in revenue-generating staff. In 2025, revenue increased to $17.2 billion, including 6% organic revenue growth, acquired revenue from NFP and a favorable currency impact. Organic growth reflects growth in the existing business rather than acquired revenue.
Aon is investing in data, analytics, technology and AI across its services. In Q3 2026, it delivered 6% organic revenue growth overall, with organic growth in both commercial risk and reinsurance. New business and retention more than offset lower reinsurance rates. Construction growth benefited from a pipeline of data-center projects.
The company expects its pending USI acquisition to close in the fourth quarter of 2026. After closing, it plans to combine USI with NFP and Aon’s existing operations to serve U.S. middle-market clients. Aon estimates that market represents more than $40 billion across commercial risk, health and wealth. It also expects USI to give it direct access to the excess and surplus insurance market, which serves risks outside standard insurance markets.
Aon has identified $395 million of expected run-rate EBITDA synergies from the transaction, including $280 million in cost synergies and $115 million in revenue synergies. Its plans include technology and efficiency measures, placement changes and selling risk and human capital services across client relationships.
- $12.2BFY2021
- $12.5BFY2022
- $13.4BFY2023
- $15.7BFY2024
- $17.2BFY2025
Structural risks
- Economic activity: An overall decline in economic and business activity could adversely affect Aon’s financial condition and results. Demand and payment collection can also be affected by conditions in the countries where it operates.
- Insurance pricing and distribution: Premium-based commissions can be challenged by alternative risk protection, reduced underwriting capacity, direct sales by insurers and technology-enabled competitors. Clients may also prefer flat fees, which are not consistently indexed for inflation.
- Legal and regulatory exposure: Aon faces errors-and-omissions claims and other legal proceedings. Its activities are extensively regulated, and authorities can impose licensing, commission and disclosure requirements across jurisdictions.
- Technology and operations: Aon relies on complex information technology systems and networks. Natural or human-caused disasters could reduce business and increase claims, while global operations bring staffing, compliance and cross-border service challenges.
- Currency: Exchange-rate fluctuations can negatively affect financial results and cash flows because Aon operates internationally.
- Transaction financing and integration: Aon expects its USI acquisition to close in the fourth quarter of 2026. It expects higher USI-related debt to raise interest expense, and its planned synergies depend on integration initiatives.
Bottom line
Our reading
Our reading: Aon is a fee- and commission-based intermediary and adviser whose business rests on client relationships, specialist staff and access to insurance capital. Its broad services and geographic reach support those relationships, while competition and changes in insurance pricing can pressure brokerage revenue. The pending USI deal offers a larger middle-market platform, but adds financing costs and makes delivery of the expected integration benefits important.