Once a player in the exploration and production field, Tesoro Corporation (formerly Tesoro Petroleum) has been enjoying a more refined existence in recent years as a downstream operator. The independent oil refiner and marketer operates six US refineries (875,000 barrels per day) -- in Alaska, California (two), North Dakota, Utah, and Washington. It produces gasoline, jet fuel, diesel fuel, fuel oil, liquid asphalt, and other fuel products. Tesoro markets fuel to more than 2,300 branded retail gas stations (including Shell, and USA Gasoline brands), primarily in Alaska and the Western US. It owns 36% of Tesoro Logistics LP (TLLP). In 2016 Tesoro agreed to acquire Western Refining in a $6.4 billion deal.