Aon’s financing arm priced senior notes across seven tranches on September 14, 2026, one of the largest single bond deals in the insurance broker’s history. The proceeds, together with a new term loan, are earmarked to fund the acquisition: Aon plc will acquire USI for a purchase price of $17 billion in cash (inclusive of net debt), agreed with KKR and other USI shareholders. Buried in the deal’s fine print is a redemption clause that could force Aon to unwind part of the financing if the USI acquisition doesn’t close on schedule.
The tranches, rate by rate
Three of the tranches anchor the curve at either end and in the middle. At the short end, Aon priced $2,000,000,000 5.350% senior notes due 2029. The single largest piece of the offering was $3,000,000,000 5.625% senior notes due 2031. At the long end, Aon sold $2,000,000,000 6.450% senior notes due 2056, a 30-year tranche that will remain outstanding long after the USI integration is complete.
The notes priced on a trade date of September 14, 2026, with settlement following on September 17, 2026, according to the pricing term sheet Aon North America filed with the SEC. The remaining tranches round out a maturity ladder stretching from the short end all the way to the 2056 notes, giving Aon a financing structure built to outlast the integration period rather than merely bridge it.
Where the rating agencies disagree
The offering drew three different verdicts from the rating agencies, and they don’t point in the same direction. Moody’s assigned Baa2 (Stable), S&P came in at A- (Negative), and Fitch went further, placing the notes at BBB+ (Ratings Watch Negative) pending the deal’s outcome. A Ratings Watch Negative tag is the sharpest of the three signals: it flags a possible downgrade tied to a specific event — in this case, whether and how the USI acquisition closes — rather than a general drift in credit quality.
S&P’s caution here isn’t unique to Aon. The agency has also cut its outlook on Acrisure Holdings to negative, citing integration risk in a separate debt-funded broker roll-up. The financing also lands weeks after Aon’s finance chief handed over the CFO seat on an interim basis. The timing isn’t all downside, though: Aon has also flagged improving primary D&O pricing trends elsewhere in the business, after a long stretch of softening.
The redemption clause built for a stalled deal
The notes carry a Special Mandatory Redemption feature that ties their fate directly to the merger timeline. If the USI acquisition hasn’t closed by the earliest of (i) June 1, 2027 (subject to two extensions of up to three months each if certain regulatory approvals remain outstanding), most of the tranches come back. Under that scenario, Aon will be required to redeem all of the outstanding USI Acquisition Notes of each series (but not the 2056 Notes) at a redemption price equal to 101% of the aggregate principal amount, plus accrued and unpaid interest. Notably, the 30-year 2056 notes are carved out of that mechanism entirely — a sign that Aon intends to keep the longest-dated piece of the financing on its balance sheet regardless of how the USI deal plays out.
Closing itself hinges on the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and receipt of other applicable regulatory approvals, and is expected to occur in the fourth quarter of 2026, according to the related prospectus supplement Aon filed with the SEC. That leaves a runway of several months between pricing and the longstop before the redemption mechanism could ever kick in.
Why the balance sheet is about to stretch
The bond sale isn’t the whole financing package. Aon North America, Inc. — the entity that priced the notes — also arranged a term loan to ANA in an aggregate principal amount of up to $4.0 billion, adding more flexibility on the cash side of the transaction. Combined, the proceeds are meant to pay the Cash Consideration, (ii) effect the USI Debt Repayment and (iii) pay fees, premiums and expenses in connection with the foregoing.
Aon has told investors it is targeting a leverage ratio (calculated by dividing total indebtedness by trailing 12-month EBITDA (earnings before interest, taxes, depreciation and amortization)) of between 2.8:1 and 3.0:1 within approximately 24 months following the completion of the USI Acquisition — an acknowledgment that leverage will climb before it comes back down. Rival broker Acrisure has meanwhile been trimming headcount as it leans on automation to manage its own cost base.
What Aon is buying, and from whom
On the seller side is KKR, the private equity firm exiting its stake in USI alongside other shareholders. KKR has stayed active elsewhere in the sector too — it joined a consortium bid to take Steadfast Group private earlier this year, part of a broader private-equity push into insurance distribution. That push shows little sign of slowing: Thoma Bravo also moved to take Accelerant private in a multi-billion-dollar deal of its own.
USI itself is no small target. Aon’s own announcement of the acquisition describes the company as the tenth largest U.S. insurance broker with approximately $3 billion in annual revenue and more than 10,500 team members across nearly 200 U.S. offices. Aon put a number on the deal — agreeing to acquire USI from KKR and other shareholders for a total purchase price of $17.0 billion, or $16.7 billion on a net basis — in a statement dated August 31, 2026. The two sides had already formalized the transaction a day earlier, on August 30, 2026, Aon plc, ANA and Merger Sub entered into an Agreement and Plan of Merger.
