Aon to acquire USI in $17B all-cash deal, targeting U.S. middle-market insurance dominance

MarketBeat Mon, August 31, 2026 at 10:01 AM PDT 5 min read

Aon (NYSE: AON) announced it has entered a definitive agreement to acquire U.S. middle-market insurance broker USI in an all-cash transaction valued at approximately $17 billion, or $16.7 billion net of certain tax attributes. The deal is expected to close in the fourth quarter of 2026, subject to regulatory approvals and customary closing conditions.

Greg Case, Aon’s president and chief executive officer, described the transaction as a move to establish what the company calls the premier U.S. middle-market platform. The combined operation would bring together Aon, USI, and NFP—which Aon previously acquired—and expand the company’s capabilities in property and casualty, employee benefits, personal risk, and retirement solutions.

Following the closing, USI Chairman and CEO Mike Sicard is expected to become Aon’s president and global CEO of Middle Market. He will lead the combined platform with leadership drawn from USI, NFP, and Aon, Case said.

Middle-Market and E&S Expansion

Aon said the transaction will deepen its presence in the U.S. middle market, which Case noted represents about one-third of the U.S. commercial property-and-casualty market. The company estimated that the segment includes more than 200,000 businesses employing roughly 48 million people and represents an addressable market of more than $40 billion.

USI has approximately $11 billion of property-and-casualty premium placement and 2,800 producers, according to Aon. The combined middle-market platform is expected to generate $6.5 billion in revenue.

The acquisition also expands Aon’s direct access to the excess and surplus (E&S) insurance market and wholesale distribution. Case said the E&S segment accounts for 26% of U.S. commercial property-and-casualty premiums and has been growing at an 18% compound annual rate. Aon noted that its existing direct presence in the segment has been limited largely to its Totalis Specialty business.

Andy Marcell, Aon’s deputy CEO and senior executive vice president of Risk Capital and Human Capital, said direct access to E&S markets would give clients greater choice and enable Aon to better serve specialty and wholesale-related business. He also said USI’s brokers would gain access to Aon’s global retail network, including relationships in London and Bermuda.

Financial Terms and Synergy Plans

Nadin Virani, Aon’s interim chief financial officer, said the $17 billion purchase price represents a 14.5-times synergized EBITDA multiple. Aon plans to finance the acquisition with newly issued debt across a range of maturities.

The company identified $395 million in expected adjusted EBITDA impacts from revenue and cost synergies across the full middle-market platform. Those plans include:

• $321 million in net revenue synergies across 23 work streams, translating to a projected $115 million EBITDA contribution.
• $280 million in cost synergies from 10 identified work streams, including technology integration, shared services, and Aon Business Services capabilities.
• Opportunities to improve producer productivity and retention, expand cross-selling between risk capital and human capital solutions, and optimize insurance premium placement.

Virani said USI would add $3.3 billion in revenue and $1.2 billion in adjusted EBITDA on a fully synergized trailing 12-month basis. Aon expects the transaction to dilute earnings per share in 2027 before becoming accretive in 2028 and thereafter.