State Automobile Mutual Insurance, informally known as State Auto Group, hosts a non-stop pool party. Through a constellation of subsidiaries, the company provides both personal and commercial property/casualty insurance in the US. It owns 65% of publicly traded State Auto Financial, which, in turn, holds a fistful of insurance subsidiaries. Collectively, the companies sell their products through more than 3,000 independent agencies in 34 states. All are part of a pooling arrangement in which State Auto Group assumes the premiums, losses, and expenses from each and returns a portion to participants based on prearranged percentages. State Auto Group keeps the balance of the pooled business.
State Auto Group's Rockhill Holding unit writes specialty surplus and excess insurance for the small and midsized commercial markets in most US states. Rockhill also provides workers' compensation products and claims administration services.
State Auto Mutual Insurance Company was founded in 1921 and has grown from a small regional player to a superregional presence through a steady stream of acquisitions. Having expanded its geographic reach, the company is now expanding its product range, as evidenced by its 2009 acquisition of Rockhill. State Auto Group is also adding additional coverage options such as flood insurance.