Aspen Insurance Holdings Limited (Aspen Holdings) is a holding company. The Company conducts insurance and reinsurance business through its subsidiaries: Aspen U.K. and AUL, Aspen Bermuda (Bermuda) and Aspen Specialty and AAIC (the United States). It operates in two segments: Aspen Insurance and Aspen Reinsurance (Aspen Re). Its insurance segment consists of property and casualty insurance; marine, aviation and energy insurance, and financial and professional lines insurance. Aspen Re consists of property catastrophe reinsurance, other property reinsurance, casualty reinsurance and specialty reinsurance. Its Aspen Re consists of property catastrophe reinsurance, other property reinsurance (risk excess, pro rata and facultative), casualty reinsurance (the United States treaty, international treaty and global facultative) and specialty reinsurance (credit and surety, agriculture, marine, aviation, terrorism, engineering).