shares of valero energy corp vlo shed 102 to 7780 monday on what proved to be an allaround rough trading session for the stock market with the sp 500 index spx falling 069 to 436119 and dow jones industrial average djia falling 072 to 3449606 the stocks fall snapped a threeday winning streak valero energy corp closed 715 short of its 52week high 8495 which the company achieved on june 3rd the stock underperformed when compared to some of its competitors monday as phillips 66 psx fell 011 to 8204 marathon petroleum corp mpc fell 092 to 6456 and hollyfrontier corp hfc fell 072 to 3444 trading volume 40 m eclipsed its 50day average volume of 37 m editors note this story was autogenerated by automated insights an automation technology provider using data from dow jones and factset see our market data terms of use