Which two oil companies merged in 1999 to form ExxonMobil?

Exxon and Mobil merged in 1999 to form ExxonMobil.

The merger combined two major descendants of Standard Oil, the enormous American oil trust broken up by the U.S. Supreme Court in 1911. Standard Oil of New Jersey later became Exxon, while Standard Oil of New York became Mobil.

Exxon and Mobil announced their agreement in December 1998, and the transaction was completed in November 1999. The combined company became one of the world’s largest publicly traded oil and gas businesses, with activities spanning exploration, production, refining, chemicals, and fuel marketing.

The merger is sometimes confused with other large oil-industry combinations, such as Chevron’s acquisition of Texaco in 2001. ExxonMobil’s name preserves both predecessor brands, making the companies involved in the 1999 transaction especially straightforward to identify.