Its undoing as an independent company began in 1982 when T. Boone Pickens, an Amarillo, Texas, oilman and corporate raider (or greenmailer), and owner of Mesa Petroleum, made an offer for the comparatively larger (but still considered "non-major" oil company) Cities Service Company (more generally known by the name Citgo) from Tulsa, Oklahoma, which was then trading in the low 20s. Pickens first privately offered $45 a share for a friendly takeover and then later made a $50 a share public offer when Cities' CEO rejected the friendly offer. Gulf forestalled Mesa's takeover attempt by offering $63 a share in a friendly offer which Cities (by then trading at $37) accepted. Cities then bought out Pickens for $55 a share. Once Pickens was gone, Gulf reneged on its buyout offer, supposedly over a dispute regarding accuracy of Cities Service's reserves, and the stock price of Cities plunged, triggering stockholder lawsuits as well as distrust for Gulf's management on Wall Street and among financing investment banks who bet big in assisting Gulf to defeat Mesa only to be left broke when Gulf backed out. Cities Service was ultimately sold to Occidental Petroleum, and the retail operations were resold to Southland Corporation, the operators of 7-Eleven stores. Gulf's termination of the Cities Service acquisition resulted in more than 15 years of shareholder litigation against Gulf (and later Chevron).