shares of american tower reit amt slid 031 to 20818 tuesday on what proved to be an allaround mixed trading session for the stock market with the sp 500 index spx rising 009 to 415487 and the dow jones industrial average djia falling 003 to 3397663 american tower reit closed 7429 short of its 52week high 28247 which the company achieved on august 15th the stock underperformed when compared to some of its competitors tuesday as crown castle inc cci rose 017 to 13240 and sba communications corp sbac fell 005 to 26305 trading volume 19 m remained 204450 below its 50day average volume of 21 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