delek us holdings (nyse: dk) is a leading diversified downstream energy company with operations in three primary business segments: petroleum refining, marketing & supply and retail. the refining segment operates a 60,000 barrel-per-day high-conversion, moderate complexity refinery in tyler, texas. the marketing & supply segment transports and sells refined products on a wholesale basis in west texas through company-owned and third-party operated terminals. the retail segment markets gasoline, diesel and other refined products through a network of more than 450 company-operated fuel and convenience stores located in eight states under a number of regional brands, including mapco express®, mapco mart® east coast®, discount food mart™, fast food and fuel™ and favorite markets® brand names.