Chevron
Chevron Corporation, parent of Chevron, Texaco and Caltex, engages in oil and gas exploration; and refining and marketing of oil, lubricants, and fuels, including gasoline, marine and aviation fuels.
BP
BP is the third largest global energy company, a multinational oil company among the largest private sector energy corporations in the world.
Exxon
Exxon is the world's largest publicly traded international oil and gas company, providing energy that helps underpin growing economies and improve living standards around the world.