Aspen Insurance Holdings is a Bermuda-based specialty insurance and reinsurance underwriter, acquired by Japanese P&C group Sompo in February 2026. Aspen writes a broad range of specialty risks globally through subsidiaries in Bermuda, the U.S., and the U.K., including a Lloyd's syndicate. Aspen operates two segments: Insurance (~59% of gross written premiums) and Reinsurance (~41%). The Insurance segment covers financial and professional lines (E&O, D&O, cyber), casualty and liability, specialty insurance (energy, political risk, crisis management), and first-party property — with roughly 69% of premiums covering U.S. and Canadian risks. The Reinsurance segment writes casualty, property catastrophe, other property, and specialty reinsurance on both treaty and facultative bases, with a more globally distributed book. Nearly all business flows through brokers, with Marsh, Aon, and Gallagher as the largest distribution partners. Aspen earns money through underwriting income and investment income on reserves held in fixed income. Aspen also runs Aspen Capital Partners, which combines its ceded reinsurance function with a third-party capital platform (ACM) that structures ILS funds, sidecars, and collateralized quota shares alongside Aspen's own balance sheet — allowing Aspen to write more premium than its own capital would support while earning management and performance fees.