Aon Announces $17 Billion Acquisition of USI

Aon has agreed to acquire USI Insurance Services from KKR and other shareholders for $17 billion, in one of the largest insurance brokerage acquisitions in recent years. The transaction strengthens Aon’s position in the U.S. middle-market segment while expanding its capabilities across insurance, risk management, employee benefits and human capital advisory services.

The deal comes as insurance brokerage and professional services firms continue to pursue scale and specialized capabilities through mergers and acquisitions. For Aon, the USI transaction builds on its $13 billion acquisition of NFP in 2024, further strengthening its presence among middle-market businesses.

Aon Expands Its U.S. Middle-Market Presence

USI Insurance Services is the 10th-largest insurance broker in the United States, generating approximately $3 billion in annual revenue. The company employs more than 10,500 people and operates nearly 200 offices across the country.

USI provides property and casualty insurance, employee benefits, personal risk, retirement and related consulting services, primarily serving middle-market businesses.

Aon sees the U.S. middle-market segment as a significant growth opportunity. The market is estimated at more than $40 billion and represents more than one-third of U.S. commercial property and casualty direct written premiums.

The acquisition will also increase Aon’s exposure to the excess and surplus (E&S) insurance market, which serves businesses with more complex or specialized risks.

Aon CEO Highlights the Strategic Value

Aon expects the combination with USI to create a stronger platform for serving middle-market companies while expanding the firm's ability to deliver data-driven and technology-enabled solutions.

“USI will substantially enhance our middle-market footprint and expand access for our firm in the E&S segment.” — Greg Case, President and Chief Executive Officer, Aon

 Greg Case also emphasized the broader opportunity presented by the transaction, noting that middle-market companies are an important part of the economy and increasingly require support for more complex business risks.

The combined platform is expected to strengthen Aon’s capabilities across risk, health, talent and human capital advisory services. Aon also expects its combined data capabilities to support the development of AI-driven solutions and provide deeper insights for clients.

USI Leadership to Join Aon

The transaction will also bring USI's senior leadership into Aon.

Following completion of the deal, Mike Sicard, Chairman and Chief Executive Officer of USI, will become President of Aon and Global CEO of its Middle Market business. He will report directly to Greg Case and join Aon’s Executive Committee.

Sicard said the transaction represents an important next stage for USI and highlighted the cultural alignment between the two organizations.

“Our firms share strong, one-firm cultures with a deep commitment to working together to bring the best of our capabilities to clients.” — Mike Sicard, Chairman and Chief Executive Officer, USI Insurance Services

His appointment is expected to play an important role as Aon integrates USI into its broader middle-market operations.

The acquisition also marks a major exit for private equity firm KKR, which acquired USI alongside Canadian pension fund CDPQ in 2017 for approximately $4.3 billion.

Under KKR's ownership, USI significantly expanded its business, with revenue nearly tripling during the investment period. KKR said the sale represents approximately a sixfold return on its original investment, while Reuters reported that the transaction is expected to generate roughly $2 billion in adjusted profit for KKR.

The transaction illustrates the potential returns available when private equity investors build scale in fragmented professional services markets before selling to a strategic buyer.

Deal Expected to Close in Q4 2026

Aon plans to fund the acquisition through new debt raised across different maturities, subject to market conditions. The purchase price is $17 billion, or approximately $16.7 billion on a net basis after taking certain tax attributes into account.

The transaction has been approved by the boards of both Aon and USI. However, the companies will continue to operate independently until the deal closes.

The acquisition is expected to close in the fourth quarter of 2026, subject to regulatory approvals and other customary closing conditions.

The Aon-USI transaction reflects a wider trend across insurance, consulting and professional services, where companies are using M&A to expand specialized expertise and strengthen their technology and data capabilities.

For Aon, USI adds scale, client relationships and middle-market expertise. It also creates an opportunity to combine Aon’s global resources and data capabilities with USI’s established presence among U.S. businesses.

The deal also demonstrates the increasing importance of AI, analytics and specialized advisory services in professional services. As businesses face more complex risks, clients are looking for advisers that can combine industry expertise with data-driven insights and technology.

With USI joining its platform, Aon is positioning itself for a larger role in the U.S. middle market and reinforcing its broader strategy of growth through strategic acquisitions.