Aon to Buy USI Insurance Services for $17 Billion 

• By: Olivia Overman
• August 31, 2026

Aon, the third-largest insurance brokerage and professional services firm, today announced the signing of a definitive agreement to acquire USI Insurance Services from KKR and other shareholders for $17 billion. The deal is expected to close in the fourth quarter of 2026.

USI, the 10th-largest U.S. insurance broker, provides property & casualty, employee benefits, personal risk and retirement solutions, with approximately $3 billion in annual revenue and more than 10,500 employees in nearly 200 offices nationwide.

The acquisition will substantially enhance Aon’s presence in the U.S. middle-market segment, building on its 2024 acquisition of NFP for $13.4 billion.

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

“Building on the success of our acquisition of NFP, USI will substantially enhance our middle-market footprint and expand access for our firm in the [excess & surplus] segment to deliver content, capabilities and expertise to a broader client base, while enabling client leaders to expand relationships and win new business,” Case said.

Aon is expected to fund the transaction and related expenses with new debt raised across a range of maturities, subject to market conditions.

Private equity firm KKR will receive $3.3 billion in after-tax cash from the sale of the insurance and employee benefits broker to insurer Aon, making a gain of about 3.4 times on the almost $1 billion that the New York-based investment group invested in the company from 2017, according to the Financial Times.

“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,” said Mike Sicard, USI chairman and CEO. “Our firms share strong, one-firm cultures with a deep commitment to working together to bring the best of our capabilities to clients.”

When the deal is finalized, Sicard will serve as president of Aon plc and global CEO of middle market, reporting to Case, and join the Aon Executive Committee.

“I look forward to leading Aon’s middle-market platform and uniting the strengths of USI, NFP and Aon to deliver a new standard of content, capabilities and service to our clients,” Sicard said.

Aon said it expects to deliver approximately $395 million in annual run-rate net adjusted EBITDA (earnings before interest, taxes, depreciation and amortization) from revenue and cost synergies from the deal.

Olivia Overman is IA content editor.