shares of marathon petroleum corp mpc shed 371 to 12378 monday on what proved to be an allaround dismal trading session for the stock market with the sp 500 index spx falling 015 to 385576 and dow jones industrial average djia falling 028 to 3181914 the stocks fall snapped a twoday winning streak marathon petroleum corp closed 1268 below its 52week high 13646 which the company achieved on january 27th the stock underperformed when compared to some of its competitors monday as exxon mobil