Sompo Holdings said Wednesday it has agreed to buy New-York-listed Aspen Insurance Holdings for about $3.5 billion, or $37.50 a share in cash. The offer represents a 35.6% premium to Aspen’s unaffected share price and values the specialty property-and-casualty insurer at roughly ¥520 billion. Aspen is majority-owned by Apollo Global Management, which took the company private in 2019 for $2.6 billion before relisting it earlier this year. Sompo will finance the acquisition entirely with internal capital; the transaction is expected to close in the first half of 2026 subject to regulatory approvals. Morgan Stanley is advising Sompo, while Goldman Sachs is working with Aspen. The deal deepens Sompo’s presence in the United States, which accounts for about 40% of the global insurance market, and adds lines such as cyber and directors-and-officers coverage. Japanese insurers have been stepping up overseas takeovers as an aging population and low yields curb growth at home, following moves such as Nippon Life’s $8.2 billion purchase of Resolution Life and Nomura’s $1.8 billion acquisition of Macquarie asset-management units.