Valero Energy Corporation is a Fortune 500 company based in San Antonio, TX.  Through its subsidiaries, Valero is an international manufacturer and marketer of transportation fuels, other petrochemical products and power. Approximately 7,400 outlets carry the Valero, Diamond Shamrock, Shamrock, and Beacon brands in the United States and the Caribbean; Ultramar in Canada; and Texaco in the United Kingdom and Ireland.