W.R. Berkley Corporation operates as an insurance holding company underwriting commercial insurance business, workers' compensation insurance products, accident and health insurance, and various other types of insurance. The company has two operating segments: Insurance and Reinsurance & Monoline Excess. The Insurance segment provides umbrella and excess liability coverage products, specialized insurance coverages, personal lines insurance solutions, various insurance products for technology, life sciences and travel industries, and at-risk and alternative risk insurance program management services, while the Reinsurance & Monoline Excess segment helps other insurance companies and self-insureds in managing their net risk.