shares of carmax inc kmx shed 374 to 10524 tuesday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 155 to 430626 and dow jones industrial average djia falling 176 to 3329495 the stocks fall snapped a threeday winning streak carmax inc closed 5074 below its 52week high 15598 which the company achieved on november 8th the stock underperformed when compared to some of its competitors tuesday as copart inc cprt fell 166 to 12084 autonation inc an fell 157 to 11286 and penske automotive group inc pag fell 275 to 9559 trading volume 17 m eclipsed its 50day average volume of 16 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