From their website:
Supreme Oil Companywas founded in 1939 by Frank Wilkinson in Phoenix, Arizona. Dale Mahan and Tom Nick purchased the assets of Supreme Oil from the estate of Frank Wilkinson Jr. in 1988. In 1992 Supreme Oil acquired the assets of Fogerty Petroleum of San Diego establishing its presence in Southern California. Garth Davis became a partner and shareholder in Supreme Oil in 1993. Supreme Oil signed an agreement to be a commercial fuel distributor for Mobil Oil Company in San Diego and Maricopa Counties in 1994. In 1998 Supreme Oil signed an agreement with Ultramar Diamond Shamrock to be a distributor.