James River Group Holdings is a holding company. Through its subsidiaries, Co. owns and operates a group of specialty insurance and reinsurance companies. Substantially all of Co.'s business is casualty insurance. Co. has three segments: Excess and Surplus (E&S) Lines, Specialty Admitted Insurance and Casualty Reinsurance. The E&S Lines segment sells E&S commercial lines liability and property insurance. The Specialty Admitted Insurance segment has admitted licenses and the authority to write excess and surplus lines insurance in various states and the District of Columbia. The Casualty Reinsurance segment provides proportional and working layer casualty reinsurance to third parties.