Aon agrees to acquire USI Insurance Services from KKR for $17 billion

Overview

Updated Sep 2

Aon agreed to buy USI Insurance Services from KKR for $17 billion in cash, one of the largest insurance-broker acquisitions in years. The deal would make Aon the largest seller of insurance and benefits to U.S. mid-sized businesses, a market of more than $40 billion in premiums.

It is Aon's second middle-market bet, following its 2024 acquisition of NFP. The deal also opens a direct route into excess-and-surplus insurance, one of the fastest-growing areas of U.S. commercial coverage.

For KKR, the sale ends a nine-year hold, returning about $3.3 billion after taxes, roughly 3.4 times its invested capital. Closing is expected in the fourth quarter of 2026, pending regulatory approval.

Why it matters

Most U.S. mid-sized employers buy insurance through brokers, and this deal decides which firm will dominate that $40 billion market.

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Key Indicators

$17.0 billion

Total purchase price

All-cash consideration Aon agreed to pay for USI.

$16.7 billion

Net purchase price

Purchase price minus about $278 million in tax attributes.

$3.3 billion

KKR's expected after-tax proceeds

Roughly 3.4 times the capital KKR invested in USI since 2017.

$395 million

Target annual synergies

Aon's projected net adjusted EBITDA gains from revenue and cost synergies.

14.5x

Purchase price multiple

Net price as a multiple of USI's adjusted earnings before interest, taxes, depreciation, and amortization.

$3 billion

USI annual revenue

Revenue of the tenth-largest U.S. insurance broker, with 10,500 employees.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Greg Case

Chief executive officer, Aon

Leading Aon's middle-market expansion

Mike Sicard

Chairman and chief executive, USI; incoming president of Aon

Will become Aon's president and global CEO of Middle Market after closing

Organizations Involved

Aon plc

Global professional services firm (insurance brokerage and consulting)

Acquirer in the $17 billion deal

Aon is the world's second-largest insurance broker, behind Marsh McLennan.

USI Insurance Services

Insurance brokerage and consulting firm

Acquisition target; will anchor Aon's middle-market platform

USI is the tenth-largest U.S. insurance broker, with about $3 billion in annual revenue.

KKR & Co. Inc.

Private equity firm

Seller; exiting its nine-year investment in USI

KKR is one of the world's largest private equity firms and the seller of USI.

NFP

Insurance brokerage and advisory firm

Aon's 2024 middle-market acquisition; part of the combined platform

NFP, formerly National Financial Partners, is the middle-market broker Aon bought in 2024, the template for the USI deal.

Timeline

2017 September 2026

3 events Latest: September 1st, 2026 · 2 months ago

September 2026
Aon agrees to buy USI from KKR for $17 billion
Latest Acquisition

All-cash deal announced; closing expected in the fourth quarter of 2026, pending regulatory approval.
September 1st, 2026
April 2024
Aon agrees to buy middle-market broker NFP
Acquisition

Aon enters the middle market by agreeing to buy NFP.
April 2024
2017
KKR and Quebec's CDPQ buy USI from Onex
Acquisition

KKR and Quebec's public pension fund CDPQ buy USI from Onex for $4.3 billion.
2017

Scenarios

Aon closes USI acquisition by end of 2026

Likely Resolves by End of 2026

Discussed by: Aon's guidance in its investor presentation; Reuters and CNBC coverage framing the deal as likely to close in Q4

Both boards have approved the deal, and Aon plans to fund it with new debt while keeping its investment-grade ratings. The main condition left is regulatory approval. Because USI is a middle-market broker rather than a direct global rival, the antitrust risk looks low. Aon has said it will pause share buybacks to pay down the debt.

Regulators delay the deal or demand divestitures

Possible Resolves by Q1 2027

Discussed by: A standard risk for large U.S. deals; Aon's own materials note closing requires regulatory approvals

The deal faces review under the Hart-Scott-Rodino Act, the federal law that requires antitrust clearance for large transactions. If the Justice Department or Federal Trade Commission issues a second request for information, closing would likely slip into 2027. Regulators could also demand that Aon sell parts of USI where the two companies overlap in local markets.

Deal collapses or is renegotiated

Unlikely Resolves by Q2 2027

Discussed by: InsuranceNewsNet, which reported that some Aon shareholders balked at the price and the added debt

Aon is funding the entire purchase with new debt, and InsuranceNewsNet reported that some shareholders questioned the price. If credit markets deteriorate or shareholder pressure builds, Aon could seek a lower price or walk away. The price is 14.5 times USI's synergized earnings, a rich multiple for a middle-market broker. A regulatory block would also end the deal.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2018 – 2019

Marsh & McLennan buys Jardine Lloyd Thompson (2018-2019)

Marsh, the world's largest insurance broker, agreed to buy London-based rival JLT, one of the biggest broker acquisitions in years. The deal combined two of the industry's best-known names and closed after clearing regulatory review.

Then

Marsh absorbed JLT's offices and staff, expanding its specialty insurance business in Britain and internationally.

Now

The deal became a reference point for how far a top-tier broker will go to buy a sizable rival rather than merge with a peer.

Why this matters now

Aon-USI follows the same pattern at a larger scale. But JLT was a global specialist, while USI is a purely U.S. middle-market firm, which changes the antitrust math.

March 2020 – July 2021

Aon's blocked merger with Willis Towers Watson (2020-2021)

Aon agreed in March 2020 to merge with rival Willis Towers Watson in a $30 billion all-stock deal that would have created the world's largest insurance broker. The Justice Department sued to block it in June 2021, arguing the combination would raise prices for employers and insurers. Aon abandoned the merger a month later.

Then

Aon walked away and continued as an independent firm, while Willis Towers Watson remained a competitor.

Now

The failure set the boundary on Aon's dealmaking: combining with a direct global peer draws antitrust fire, but buying middle-market brokers does not.

Why this matters now

It explains why Aon is buying USI rather than another global rival. The antitrust ceiling that killed the Willis Towers Watson merger does not apply the same way to the fragmented middle market.

2017

KKR's original buyout of USI (2017)

KKR and Quebec's CDPQ pension fund bought USI from private equity firm Onex at a $4.3 billion valuation. KKR made three additional investments in the company over the next nine years.

Then

USI grew to roughly $3 billion in annual revenue and 10,500 employees across nearly 200 U.S. offices.

Now

The sale to Aon returns about 3.4 times KKR's balance-sheet capital, an example of the buy-build-sell model private equity firms apply across the fragmented brokerage industry.

Why this matters now

The USI story is a private equity hold-and-build: buy a mid-sized broker, invest more capital, sell to a strategic buyer. Aon's purchase is the exit that made the nine-year hold pay off.