Yacimientos Petrolíferos Fiscales Bolivianos (YPFB) is a Bolivian state-run company engaged in the areas of oil and gas and derivatives exploration, production, refining, transportation and distribution. Headquartered in La Paz, the company was founded in 1936. It was later privatized before being nationalized in 2006. YPFB has eight subsidiaries throughout the production and supply chain. The upstream units are YPFB Andina, YPFB Petroandina and YPFB Chaco, while YPFB Transporte and YPFB Transierra are midstream units. YFPB Refinación, YPFB Logística and YPFB Aviación are in charge of downstream operations.