shares of union pacific corp unp slid 089 to 21300 tuesday on what proved to be an allaround rough trading session for the stock market with the sp 500 index spx falling 034 to 452003 and dow jones industrial average djia falling 076 to 3510000 this was the stocks second consecutive day of losses union pacific corp closed 1826 short of its 52week high 23126 which the company reached on may 10th despite its losses the stock outperformed some of its competitors tuesday as canadian national railway co cni fell 308 to 12283 csx corp csx fell 153 to 3151 and norfolk southern corp nsc fell 090 to 24815true trading volume 38 m eclipsed its 50day average volume of 27 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