Onex & AIG to buy Convex for $7B; founders retain major stake

Onex Corporation and American International Group (AIG) have struck a definitive agreement to purchase specialist reinsurer Convex for $7 billion, the buyers and sellers said. The buyers will acquire the business from founding investors led by Onex Partners V and other institutional backers, with the deal expected to complete in H1 2026, subject to regulatory and customary closing conditions.

Convex was launched in 2019 by industry veterans including Stephen Catlin and Paul Brand, and scaled quickly as a focused player in specialty property and casualty (re)insurance. Management will maintain a substantial economic stake post-transaction, a move the buyers say preserves operational continuity and aligns incentives across the ownership group.

Since inception Convex has reported rapid top-line growth and attractive returns: management projects roughly $6 billion of gross premium written in 2025, having delivered approximately 25% compound annual growth in gross written premium over the past three years, alongside an almost 18% average return on equity across the same period. Those metrics helped position Convex as one of the faster-scaling specialist underwriters in a market where disciplined capital and underwriting expertise are increasingly prized.

For Onex Partners, the sale continues a pattern of exits from founder-led, insurance-focused investments. Adam Cobourn, a managing director at Onex Partners, praised Convex’s leadership and operational gains since launch, saying the transaction delivers strong outcomes for the fund’s limited partners at an intended pace. The sale follows earlier partial realizations from the same fund this year, underscoring a broader effort to return capital to investors while capturing value created through active ownership.

The deal highlights strategic interest from both private equity and large insurers in securing specialty underwriting capacity and long-term earnings streams. For Onex Corporation, the acquisition supports a diversified private capital platform; for AIG, it represents an opportunity to deepen access to specialty lines and redeploy capital across reinsurance and insurance solutions. Industry participants say such tie-ups reflect a wider trend: insurers and financial sponsors are consolidating scale in niches where underwriting expertise commands premium pricing and stable returns.

If completed in the first half of 2026 as planned, the transaction will be among the larger insurer M&A deals of the year and may set valuation benchmarks for comparable specialty platforms.