HollyFrontier Corp. is an independent petroleum refiner and marketer. It specializes in gasoline, diesel fuel, jet fuel, and modified asphalt. The firm operates through the following segments: Refining; Lubricants and Specialty Products; and Holly Energy Partners, LP (HEP). The Refining segment includes the operations in El Dorado, Tulsa, Navajo, Cheyenne, and Woods Cross Refineries. The Lubricants and Specialty Products segment offers base oil production activities, by-product sales to third parties, and intra-segment base oil sales to rack forward which includes the purchase of base oils and the blending, packaging, marketing and distribution and sales of finished lubricants and specialty products to third parties. The HEP segment relates to all of the operations of HEP. The company was founded in 1947 and is headquartered in Dallas, TX.