The refining giant is going through some big changes. Earlier this year, Valero announced that it planned to spin off its retail business, called CST Brands, a move that the board approved in April 2013. Shareholders like the strategy, and the company’s share price has been increasing, overall, since the initial announcement. Valero remains the world’s largest independent refiner, with 16 refineries and ethanol plants across the U.S., Caribbean, the United Kingdom and Canada. Profit margins continue to be tight for the refining business, but as more and more oil and gas companies shed their refineries, Valero remains one of the most powerful games in town.