shares of public storage psa shed 245 to 28833 thursday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 064 to 453741 and dow jones industrial average djia falling 067 to 3528272 public storage closed 6880 short of its 52week high 35713 which the company achieved on august 18th the stock underperformed when compared to some of its competitors thursday as extra space storage inc exr fell 178 to 14199 and cubesmart cube fell 171 to 4361 trading volume 627848 remained 233446 below its 50day average volume of 861294 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