Mayer Electric Supply, 3405 4th Ave S, Birmingham, AL 35222, US

ProAssurance Corporation is a specialty insurer with $3 billion in assets and more than $740 million in gross written premiums, making it the nation's fourth-largest medical liability insurance company and a leading writer of personal lines of insurance in the state of Michigan. The company does business in two insurance segments, professional liability and personal lines. Through its wholly owned professional liability subsidiaries The Medical Assurance Company, ProNational Insurance, Red Mountain Casualty Insurance and WoodBrook Casualty Insurance ProAssurance insures more than 23,000 physicians and other health care risks. ProAssurance's personal lines subsidiary, MEEMIC Insurance Company, provides auto, homeowners, umbrella and boat coverage, primarily for educational employees and their families in Michigan, where it's the 10th-largest writer of personal automobile insurance. Headquartered in Birmingham, Ala., ProAssurance was formed by the combination of Medical Assurance and Professionals Group in June 2001.