W. R. Berkley Corporation, an insurance holding company, operates as commercial lines writers primarily in the United States. The company operates in five segments: Specialty, Regional, Alternative Markets, Reinsurance, and International. The Specialty segment underwrites risks within the excess and surplus lines market, including premises operations, commercial automobile, property, products liability, and professional liability lines. The Regional segment provides insurance products and services to small-to-mid-sized businesses, and state and local governmental entities primarily in 45 states and the District of Columbia. The Alternative Markets segment offers insurance products, analytical tools, and risk management services, including loss control and claims management that enable clients to select their risk tolerance and manage it appropriately. This segment specializes in insuring, reinsuring, and administering self-insurance programs and other alternative risk transfer mechanisms for clients, such as commercial and governmental entity employers, employer groups, insurers, and other groups or entities seeking ways to manage their exposure to risks. In addition, this segment provides various services, including claims, administrative and consulting services. The Reinsurance segment offers other insurance companies and self-insureds with assistance in managing their net risk through reinsurance on a portfolio basis through treaty reinsurance or on an individual basis through facultative reinsurance. The International segment underwrites specialty, casualty, property, automobile, group life and health, workers' compensation, professional indemnity, directors' and officers' liability, medical malpractice, general liability, personal accident and travel, engineering and construction, and surety lines of business in approximately 40 countries. The company was founded in 1967 and is based in Greenwich, Connecticut.