shares of carmax inc kmx slid 787 to 8980 wednesday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 404 to 392368 and dow jones industrial average djia falling 357 to 3149007 the stocks fall snapped a fourday winning streak carmax inc closed 6618 below its 52week high 15598 which the company achieved on november 8th the stock demonstrated a mixed performance when compared to some of its competitors wednesday as copart inc cprt fell 609 to 10655 autonation inc an fell 1000 to 11039 and penske automotive group inc pag fell 778 to 10879 trading volume 22 m eclipsed its 50day average volume of 20 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