Aon agreed to acquire USI Insurance Services from private equity firm KKR for $17 billion in an all-cash deal announced August 31, 2026, in one of the largest insurance brokerage acquisitions in recent years. The transaction, expected to close in the fourth quarter of 2026 subject to regulatory approval, will establish what Aon CEO Greg Case called the “premier U.S. middle-market platform” and represents a significant expansion of the global insurance broker’s presence in the fast-growing middle-market segment.
USI, headquartered in Valhalla, New York, is the tenth-largest U.S. insurance broker with approximately $3 billion in annual revenue and more than 10,500 employees across nearly 200 offices. The firm provides property and casualty, employee benefits, personal risk, program and retirement solutions to mid-sized businesses. Following the deal’s close, USI Chairman and CEO Mike Sicard will serve as President of Aon and global CEO of its Middle Market division, reporting directly to Case and joining the Aon Executive Committee.
The acquisition builds directly on Aon’s $13 billion purchase of middle-market broker NFP, which closed in April 2024. When Aon acquired NFP in 2024, the firm signaled its commitment to dominating the middle-market segment, which exceeds $40 billion in annual value and represents more than one-third of U.S. commercial property and casualty direct written premiums. The USI deal accelerates this strategy while also expanding Aon’s access to the excess-and-surplus (E&S) insurance segment, which Aon identified as one of the fastest-growing areas in U.S. commercial insurance.
Aon plans to fund the transaction through new debt, with the firm expecting to maintain its current credit ratings of Baa2 with Moody’s and A- with S&P. The company does not expect to repurchase shares in the near term, prioritizing debt repayment instead. Aon estimates the deal will generate $395 million in annual run-rate net adjusted EBITDA impact from revenue and cost synergies across the combined middle-market platform and is expected to be accretive to adjusted earnings per share in 2028.
The sale represents a major exit for KKR, which acquired USI alongside Canadian pension fund Caisse de dépôt et placement du Québec in 2017 for approximately $4.3 billion. According to KKR, the transaction delivers roughly six times the firm’s return on its 2017 investment and a 3.4 times return on total capital invested across the life of the holding. Under KKR’s ownership, USI nearly tripled its revenue, expanding from a mid-market specialist into one of the nation’s largest brokers.
The deal underscores a broader trend of mega-acquisitions in the highly fragmented U.S. insurance brokerage sector. Arthur J. Gallagher closed a $13.5 billion acquisition of AssuredPartners in 2025, while Brown & Brown finalized a nearly $10 billion purchase of Accession Risk Management the same year. These large-scale consolidations reflect how major brokers are willing to pay substantial multiples to expand their market reach and competitive positioning, particularly in high-growth segments like the middle market.
Sources
- Reuters — confirmed the $17 billion deal announcement, expected Q4 2026 close, USI’s $3 billion annual revenue, KKR’s 6x return on 2017 investment and 3.4x return on total capital, and comparable large broker deals.
- Aon press release — detailed the strategic rationale, $395 million in annual synergies, expected 2028 EPS accretion, and Mike Sicard’s appointment as President of Aon and global CEO of Middle Market.
- KKR press release — confirmed the sale details and KKR’s return metrics on the 2017 investment.
- Yahoo Finance — reported all-cash deal structure and expected Q4 2026 closing.
