$MPC +164% YTD vs $PSX +116%: Weighing Two Leading Refiners (See the latest news for any ticker on Tickeron.) Marathon Petroleum (MPC) has delivered stronger year-to-date returns of approximately 164% compared to Phillips 66 (PSX) at around 116% through recent market activity. Both companies operate in the oil refining and marketing sector, with MPC maintaining a larger refining capacity of 3.0 million barrels per day versus PSX at 2.0 million barrels per day.