A wholly owned subsidiary of Sompo International Holdings Ltd. has completed its $3.5 billion acquisition of Aspen Insurance Holdings Ltd., officially taking the insurer private in a blockbuster deal that reshapes the global insurance landscape — and signals even bigger moves ahead.
Under the terms of the deal, first unveiled in August 2025, 100% of Aspen’s outstanding Class A ordinary shares have been acquired, and the company will no longer trade on the New York Stock Exchange. Aspen now operates as a wholly owned subsidiary of Endurance Specialty Insurance Ltd., a unit of Sompo International Holdings Ltd.. Both companies ultimately sit under the umbrella of Sompo Group—a move that tightens Sompo’s grip on the global specialty insurance market and sets the stage for its next strategic push.
(In 2017, Sompo Group snapped up Endurance Specialty Holdings Ltd. for $6.3 billion, transforming it into a global platform designed to accelerate growth across the U.S. and Europe—a bold bet that continues to shape the company’s international expansion strategy today.)
Aspen will now operate under the umbrella of Sompo Group and transition to the Sompo brand, marking a new chapter for the specialty insurer. Mark Cloutier, Aspen’s former executive chairman and group chief executive officer, will remain closely involved, stepping into an advisory role to help guide the integration and shape the company’s next phase of growth.
“Today marks an important milestone in our strategy to continue Sompo’s plans for profitable growth, to deploy capital strategically and to ensure a globally diversified property & casualty (P&C) platform. I am pleased to welcome the Aspen team to Sompo,” according to Mikio Okumura, CEO of Sompo Group, in a statement.
“This transaction continues our commitment to invest in and grow our global P&C footprint through market cycles,” commented James Shea, CEO of Sompo P&C.
“The addition of Aspen’s reinsurance and insurance portfolios along with a more substantial presence in the UK enable us to accelerate our commitments to our customers, people and shareholders,” Shea continued. “We look forward to welcoming our new colleagues and continuing to build our global portfolio through investments in people and technology. Aspen’s culture of underwriting and customer focus will ensure a smooth transition as we engage as one organization with our customers and partners.”
As for the advisers behind the deal, Sompo Group tapped Morgan Stanley & Co. LLC as its exclusive financial adviser, with Skadden, Arps, Slate, Meagher & Flom LLP serving as legal counsel. Oxbow Partners supported the integration process, while Kekst CNC acted as strategic communications adviser—assembling a heavyweight team to steer one of the industry’s most closely watched transactions.
On Aspen’s side, Goldman Sachs & Co. LLC led the financial advisory team, joined by Insurance Advisory Partners LLC as co-adviser. Sidley Austin LLP served as legal counsel—bringing together a seasoned lineup to navigate one of the sector’s most high-profile deals.
