Shell Competitor is a term used to refer to the five major oil companies that compete with Shell Oil Company. These companies are AMOCO, Esso, Mobil, ARCO, and Hess. AMOCO is a multinational oil and gas company based in the United States, while Esso is a brand name of ExxonMobil, an American multinational oil and gas corporation. Mobil is another American oil and gas company, and ARCO is a brand name of Atlantic Richfield Company, an American oil company. Lastly, Hess is an American global independent energy company.