shares of merck  co inc mrk dropped 031 to 8129 wednesday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 097 to 453276 and dow jones industrial average djia falling 096 to 3502865 the stocks fall snapped a threeday winning streak merck  co inc closed 1011 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 wednesday as johnson  johnson jnj fell 031 to 16658 roche holding ag part cert rhhvf rose 082 to 39868 and pfizer inc pfe fell 105 to 5354 trading volume 112 m remained 20 million below its 50day average volume of 131 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