ACE was established in Bermuda in 1985 by 34 founding sponsors to combat the lack of available coverage in the U.S. insurance marketplace.

Since 1985, ACE has evolved from a monoline excess insurer owned by its policyholders to a global publicly traded insurance company and one of the world's leading providers of commercial property and casualty insurance.

Opening its first office in Hamilton, Bermuda in 1986 ACE Bermuda offered excess liability and excess directors and officers liability coverage. In 1987 ACE Bermuda assumed management of Corporate Officers & Directors Assurance Ltd. (CODA), a specialist D&O underwriter which it went on to aquire in 1993.

In 1994 ACE Bermuda opened a London representative office followed by a Dublin operation in 1997, writing the same high level excess capacity for international clients.

ACE expanded its Bermuda operations to include reinsurance capabilities, acquiring Tempest Re in 1996 and CAT Limited in 1998 and creating ACE Tempest Re Bermuda, a leading Bermuda-based catastrophe reinsurance company. Tempest Re and CAT Limited, both mono-line property catastrophe reinsurers were established in response to the dislocation of the catastrophe reinsurance market following Hurricane Andrew in 1993.

ACE Bermuda formed Sovereign Risk Insurance Ltd. a specialized Bermuda-based political risk insurance and reinsurance underwriter in 1997 with strategic partners XL Insurance Company, Ltd. Sovereign restructured its ownership and became 100% owned by ACE Bermuda Insurance Ltd., on February 1, 2006.