Saudi Aramco (Arabic:أرامكو السعودية‎ ʾArāmkō s-Saʿūdiyyah), officially the Saudi Arabian Oil Company, most popularly known just as Aramco (formerly Arabian-American Oil Company), is a Saudi Arabian national petroleum and natural gas company based in Dhahran. Saudi Aramco's value has been estimated at anywhere between US$1.25 trillion and US$10 trillion, making it the world's most valuable company.