Insurance brokerage and consulting firm was a major investment for La Caisse in 2017
Aon is to acquire insurance brokerage USI Insurance Services from private-equity firm KKR & Co. for $17 billion, including debt.
The global financial services firm confirmed the deal on Monday (August 31).
"In a time of rising complexity and volatility, creating better outcomes for clients across their risk and people challenges requires a combination of capabilities and expertise supported by proprietary data, analytics and technology," said Greg Case, President and CEO of Aon. "Through the successful execution of our 3x3 Plan to accelerate our Aon United strategy, we have significantly strengthened our firm to build the industry's most differentiated model: what we call our context advantage."
The potential transaction stands out not only for its size but for its direction.
At a time when private equity firms have dominated acquisition activity across financial services, buying up brokerages, registered investment advisors, and wealth management platforms at a rapid rate.
This deal sees a publicly traded, diversified financial services company absorbing a major PE-held asset.
The move reinforces Aon's ambition to deepen its presence across the full spectrum of financial services, from risk management to employee benefits to retirement wealth.
A strategic fit for Aon's midmarket push
USI Insurance Services, headquartered in Valhalla, New York, is one of the largest insurance brokerage and consulting firms in the United States, with approximately $3 billion in annual revenue, according to its website.
The firm specializes in risk management, employee benefits, and retirement consulting, serving businesses ranging from small employers to large corporations.
USI Chairman and CEO Mike Sicard will serve as President of Aon plc and global CEO of Middle Market, reporting to Case, and join the Aon Executive Committee.
"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 Sicard. "Our firms share strong, one-firm cultures with a deep commitment to working together to bring the best of our capabilities to clients. 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."
For Aon, the acquisition is about reach. The firm, which had a market capitalization of approximately $75 billion as of Friday, has long specialized in commercial risk, reinsurance, and retirement benefits for large enterprises.
Adding USI significantly expands Aon's foothold in the midsize-business segment; a market where competition among brokers and consultants has intensified considerably in recent years.
The deal is expected to increase Aon's earnings per share as soon as 2028, a person familiar with the matter told the Wall Street Journal.
Aon also operates a wealth advisory business in the United States through its investment consulting and advisory arm, Aon Investments USA Inc., providing institutional investment consulting services to pension funds, endowments, and other large pools of capital. The addition of USI's retirement consulting capabilities could complement that platform.
The deal is a rare PE exit
KKR acquired USI alongside Canadian investment firm Caisse de dépôt et placement du Québec (CDPQ) from private-equity firm Onex Corporation in 2017 for $4.3 billion, including debt.
KKR subsequently made additional investments of more than $1 billion in the business, becoming its largest shareholder, Reuters reported. At the reported $17 billion valuation, the exit would represent a dramatic return on that original investment.
The USI deal is Aon's second major acquisition of a PE-backed financial services firm in roughly two years. In 2024, Aon completed its acquisition of NFP Corp., a middle-market property and casualty insurance broker, for approximately $13.4 billion in cash and stock from Madison Dearborn Partners and HPS Investment Partners.
The NFP transaction had its own ripple effects in the wealth management sector. Madison Dearborn subsequently acquired the bulk of Aon's NFP wealth business including Wealthspire Advisors, for approximately $2.7 billion in 2025, in what became a landmark transaction in the registered investment advisor consolidation space.
The willingness to sell the wealth business while doubling down on commercial insurance and benefits brokerage signals where Aon sees its core competitive advantage: at the intersection of corporate risk, benefits administration, and institutional retirement - precisely the territory USI occupies.
