Superior Underwriters was an established business in 1967 when Groninger & Co. acquired the company. Groninger & Co. was an established Seattle company that specialized in general accidents, and Superior Underwriters was focusing on speciality and unique risks. Groninger & Co. continued to grow to include individually specialized insurance companies throughout the north west. Superior Underwriters has continued to serve individuals and businesses with specialized risks.
Its offices near the northern tip of Samammish Lake are situated in the low and comfortable Limited Edition business campus.