Not surprisingly, the Circle K c-store chain arose from an acquisition. In 1951 entrepreneur Fred Hervey purchased three Kay's Food Stores in El Paso, Texas, retaining and encircling the “K” to create a new brand. He expanded the chain into New Mexico and Arizona, and by 1975, there were 1,000 Circle K stores.

In 1996, The Circle K Corp., then based in Tempe, Ariz., sold the Circle K chain to Stamford, Conn.-based refiner Tosco Corp., which was seeking to boost its branded downstream presence, for $710 million. Houston-based Phillips Petroleum (See No. 2) acquired Tosco in 2001 for $7.49 billion in a deal that included the Circle K stores. In 2002, Phillips merged with Conoco to form ConocoPhillips.

In December 2003, Laval, Quebec-based Couche-Tard acquired the Circle K chain from ConocoPhillips for $830 million. The transaction included 1,663 locations in 16 states and the Circle K brand, as well as more than 350 franchised and licensed stores.

For ConocoPhillips, the sale was a part of its rationalization of its downstream portfolio to focus on its wholesale business, said Jim Nokes, then ConocoPhillips' executive vice president of refining, marketing, supply and transportation.