Mexico carried out the 1938 oil expropriation that led to the creation of Pemex.
On 18 March 1938, Mexican president Lázaro Cárdenas announced the nationalization of the country's petroleum industry. The government took control of foreign-owned oil facilities after a labor dispute with oil companies and a constitutional claim that Mexico owned its subsoil resources.
The expropriation reorganized production, refining, and distribution under state control. Petróleos Mexicanos, commonly called Pemex, was established later in 1938 to manage the nationalized industry and became one of Mexico's most important state enterprises.
The event is often called the Mexican oil expropriation or oil nationalization. It is different from Mexico's earlier 1917 constitutional declaration of subsoil ownership: the 1938 action was the direct takeover of operating oil assets.