James River Group Holdings, Ltd. is an insurance holding company. The Company owns and operates a group of specialty insurance and reinsurance companies. The Company operates through four segments: Excess and Surplus Lines, Specialty Admitted Insurance, Casualty Reinsurance, and Corporate and Other. The Excess and Surplus Lines segment offers excess and surplus commercial lines liability and property insurance. The Specialty Admitted Insurance segment focuses on a range of markets within the standard insurance markets, such as workers' compensation coverage for residential contractors, light manufacturing operations, transportation workers and healthcare workers. The Casualty Reinsurance segment provides proportional and working layer casualty reinsurance to third parties and to the United-based insurance subsidiaries. The Corporate and Other segment consists of the management and treasury activities of its holding companies and interest expense associated with its debt.