Chevron Corporation (NYSE: CVX; commonly known as Chevron) is an American multinational energy corporation headquartered in San Ramon, California, United States. It operates in more than 180 countries. Chevron is engaged in the oil, gas, and geothermal sectors, including exploration and production; refining, marketing and transport; chemicals manufacturing and sales; and power generation. Chevron is one of the world's six "supermajor" oil companies. For the past five years (through 2012) Chevron has been ranked as America's third largest corporation in the Fortune 500 In 2011 it was named the 16th largest public company in the world by Forbes Global 2000. Chevron is one of the largest corporations in the world by revenue.