W. R. Berkley Corporation is an American commercial lines property and casualty insurance holding company organized in Delaware and based in Greenwich, Connecticut. The company operates commercial insurance businesses in the United Kingdom, Continental Europe, South America, Canada, Mexico, Scandinavia, Asia and Australia and reinsurance businesses in the United States, United Kingdom, Continental Europe, Australia, the Asia-Pacific region and South Africa. The company is ranked 397th on the Fortune 500. Wikipedia