shares of merck  co inc mrk dropped 097 to 8607 monday on what proved to be an allaround grim trading session for the stock market with the sp 500 index spx falling 002 to 439169 and dow jones industrial average djia falling 011 to 3441169 the stocks fall snapped a twoday winning streak merck  co inc closed 533 below its 52week high 9140 which the company achieved on november 4th the stock demonstrated a mixed performance when compared to some of its competitors monday as johnson  johnson jnj fell 125 to 17766 roche holding ag part cert rhhvf fell 005 to 41000 and pfizer inc pfe fell 241 to 5184 trading volume 73 m remained 45 million below its 50day average volume of 118 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