shares of arthur j gallagher  co ajg slumped 046 to 19565 tuesday on what proved to be an allaround rough trading session for the stock market with the sp 500 index spx falling 020 to 399097 and dow jones industrial average djia falling 114 to 3391085 arthur j gallagher  co closed 586 short of its 52week high 20151 which the company achieved on december 2nd despite its losses the stock outperformed some of its competitors tuesday as marsh  mclennan cos mmc fell 079 to 17201 trading volume 692906 remained 72760 below its 50day average volume of 765666 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