Zenith National Insurance Corp. is an indirect wholly-owned subsidiary of Fairfax Financial Holdings Limited. Zenith National Insurance Corp. is the holding company for Zenith Insurance Company and its subsidiaries, including ZNAT Insurance Company ("Zenith").  The insurance subsidiaries of Zenith National Insurance Corp. are independently rated and have received an A (Excellent) rating from A.M. Best Company.

“The rating reflects Zenith's excellent capitalization, historically strong operating performance and management's expertise and commitment to maintaining underwriting discipline throughout market cycles,” according to A.M. Best. “Zenith has demonstrated a significant loss ratio advantage within the workers' compensation line, reflective of management's demonstrated commitment to adequate risk pricing.”

A.M. Best Company is a global full-service credit rating agency dedicated to serving the insurance industry. It began assigning credit ratings in 1906, making it the first of today's rating agencies to use symbols to differentiate the relative creditworthiness of companies. Best's credit ratings are independent opinions regarding the creditworthiness of an issuer or debt obligation. Best's credit ratings are based on a comprehensive quantitative and qualitative evaluation of a company's balance sheet strength, operating performance and business profile, or, where appropriate, the specific nature and details of a debt security.