Aon to Buy USI Insurance in $17 Billion Deal

Insurance brokerage Aon is buying rival USI Insurance Services from KKR and other shareholders in a $17 billion deal that will further expand its reach to midsize U.S. businesses.

The companies announced the transaction on Monday, saying they expect it to close in the fourth quarter of 2026, subject to regulatory approvals and other customary conditions.

USI, according to a press release announcing the deal, is the 10th-largest insurance broker in the United States, with approximately $3 billion in annual revenue, more than 10,500 employees, and nearly 200 offices nationwide.

The company provides property and casualty insurance, employee benefits, personal risk and retirement services.

Aon said the acquisition will substantially extend its push into the more than $40 billion U.S. middle-market segment, which accounts for more than one-third of U.S. commercial property and casualty insurance premiums.

The deal will also give Aon greater access to the excess and surplus (E&S) insurance market.

The E&S market provides coverage for risks that traditional insurers may be unwilling or unable to underwrite. It represents about 26 percent of U.S. commercial property and casualty premiums, according to Aon.

“Combining with USI will establish the premier U.S. middle-market platform, deepen our context advantage and position Aon to accelerate organic growth,” Aon president and CEO Greg Case said in a statement.

Aon expects the combined middle-market business to generate about $395 million a year in additional earnings from cost savings and higher revenue. The company said the deal should begin adding to adjusted earnings per share in 2028.

Aon plans to fund the acquisition and related expenses with new debt. After the deal closes, the company expects to focus on reducing that debt rather than buying back shares in the near term.

Once the deal is closed, USI chairman and CEO Mike Sicard will become Aon’s president and global CEO of middle market. 

“Joining Aon represents a truly energizing next chapter for our firm and an opportunity to accelerate our momentum as part of the Aon United platform,” Sicard said.

The merger builds on Aon’s $13 billion acquisition of NFP in April 2024, another major insurance brokerage focused on middle-market clients.

Aon later sold most of NFP’s wealth-management business back to private-equity firm Madison Dearborn Partners for about $2.7 billion. The sale reflected Aon’s effort to focus NFP more closely on its core risk, insurance, and employee-benefits businesses.

The USI acquisition is also a major exit for KKR, which acquired the brokerage in 2017 alongside Canadian pension fund CDPQ for about $4.3 billion. KKR subsequently invested more than $1 billion in the company and became its largest shareholder.