The Exxon predecessor is Esso, which was founded in 1912 as the Standard Oil Company of New Jersey. It was the largest oil refiner in the world at the time and was a subsidiary of Standard Oil. In 1972, the company changed its name to Esso, which is an acronym for the phrase 'S.O., Standard Oil'. In 1999, Esso merged with Mobil to form ExxonMobil, which is now one of the largest oil companies in the world.