National Iranian Oil Company

National Iranian Oil Company is Iran's state-owned oil company, headquartered in Tehran, responsible for essentially all of the country's oil and gas exploration, production and export. Its roots trace to 1951, when Iran nationalized the Anglo-Iranian Oil Company's holdings under Prime Minister Mohammad Mossadegh, and the company was reorganized under its current name and structure in the years that followed. National Iranian Oil Company holds some of the largest proven oil and natural gas reserves of any company in the world, drawing on giant fields such as Ahvaz and Gachsaran, and its operations have been repeatedly constrained over the decades by international sanctions targeting Iran's energy sector.