Aon: insurance broker profile

Overview

Aon is one of the three largest publicly traded insurance brokers, along with Marsh McLennan and WTW. It reported full-year 2025 total revenue of $17,181 million, up 9% from $15,698 million in 2024, with organic growth of 6%, in its results release of January 30, 2026. Its 2025 Form 10-K, filed in February 2026, reports about 60,000 employees at December 31, 2025, and Greg Case is president and chief executive.

The company is incorporated in Ireland. Its 10-K lists its principal executive office at 15 George's Quay in Dublin, and the filing also names global broking centers in London, Bermuda and Singapore. Its stock trades on the New York Stock Exchange under AON.

In 2025 Aon reported two reporting groups: Risk Capital, with $11,290 million of revenue before intercompany eliminations, and Human Capital, with $5,907 million. Risk Capital includes Commercial Risk Solutions and Reinsurance Solutions; Human Capital covers health, retirement and talent businesses.

History

We could not confirm a founding year from Aon's own current pages, so this profile does not state one. The firm's modern identity is the product of acquisitions and a series of changes of legal home. The point that matters most to a buyer is the more recent set of deals, listed below.

Services

Commercial Risk Solutions is the retail broking side. It places property, casualty, cyber, financial and professional liability, and sells risk consulting and analytics to large corporate buyers, often through programs involving captive insurance company structures and large self-insured retentions. Reinsurance Solutions places reinsurance for insurers and is part of how capacity reaches the primary market. Health Solutions and retirement and investment consulting advise employers on benefits design and funding. Through NFP, Aon also serves the middle market with property and casualty broking and employee benefits.

Who it serves

Aon's core client is a large or multinational company with complex risks and a risk manager or CFO who buys on a global program basis. The NFP acquisition widened the reach to mid-sized employers that buy through a local agency model, and the pending USI purchase would add a large U.S. middle-market broker to that platform. Smaller businesses typically buy through other channels. For a view of how global, regional and local brokers differ, see independent agent, broker, captive agent or direct? and how to choose a commercial insurance broker.

How it is paid

Aon's 2025 Form 10-K says the business generates revenue primarily through commissions, with compensation from insurers and reinsurers, and through fees from clients for advice and consulting services, which depend on the extent and value of the services provided. The filing also describes fees and commissions for administrative services and consulting and analytics paid by insurers. The excerpt we reviewed did not use the terms "supplemental" or "contingent" commissions, so we do not characterize them here. Ask any broker for its compensation disclosure in writing. how commercial insurance brokers get paid explains commission, fee and contingent models.

Recent deals

• USI (pending): on August 31, 2026 Aon announced an agreement to buy USI Insurance Services from KKR and other shareholders for a total purchase price of $17.0 billion ($16.7 billion net of about $278 million of tax attributes), which Aon says is about 14.5 times synergized trailing-twelve-month adjusted EBITDA. Aon said it would fund the deal with new debt and expected to close in the fourth quarter of 2026, subject to regulatory approvals; until then the companies operate independently. USI chairman and CEO Mike Sicard is to become president of Aon plc and global CEO of Middle Market after closing. Aon expects about $395 million of annual run-rate net adjusted EBITDA impact from synergies, and expects the deal to add to adjusted earnings per share in 2028 and after. Insurance Journal reported that Aon raised $13.5 billion in a bond sale in September 2026 to help fund it. The deal was not complete when we checked.
• NFP: Aon completed its purchase of NFP on April 25, 2024. Aon's announcement put the enterprise value at $13.0 billion, made up of $7.0 billion in cash and assumed liabilities and $6.0 billion in Aon stock. The sellers were Madison Dearborn Partners and funds affiliated with HPS Investment Partners. NFP kept its name as an "independent and connected" unit.
• NFP wealth sale: announced September 3, 2025, and completed October 30, 2025. Aon sold the significant majority of NFP's wealth businesses, including Wealthspire Advisors, Fiducient Advisors and Newport Private Wealth, back to Madison Dearborn Partners. Trade coverage put total consideration at about $2.7 billion and after-tax cash proceeds at about $2.2 billion. Aon reported a $1,199 million gain for 2025 in its results release.
• Other 2025 activity: the results release refers to unnamed acquisitions during 2025 with $394 million of acquisition spending, and to a divestiture of Stroz Friedberg. We could not verify dates for those.

The wider pattern is in private equity and the consolidation of insurance brokers.

Strengths and weaknesses

Aon's strengths are global placement capacity, deep analytics and a reinsurance arm that sees both sides of the market. It brings consulting and broking together for large risk and benefits programs.

Its limits are those of any very large firm. The firm focuses on large accounts, so a small employer is not its natural client. The 2024 NFP purchase and the 2025 sale of NFP's wealth units mean the group's shape has changed twice in two years, and anyone dealing with an NFP office should confirm which Aon entity holds the broker-of-record relationship and who is compensated by whom.

• Strengths: global reach; analytics and reinsurance expertise; benefits and retirement consulting in the same group.
• Weaknesses: a large-account focus; rapid restructuring in 2024 and 2025; compensation structure that needs explicit disclosure.

How to contact Aon