shares of merck  co inc mrk shed 016 to 8121 monday on what proved to be an allaround great trading session for the stock market with the sp 500 index spx rising 071 to 457552 and the dow jones industrial average djia rising 027 to 3495589 the stocks fall snapped a fourday winning streak merck  co inc closed 1019 short of 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 rose 051 to 17783 roche holding ag part cert rhhvf fell 334 to 39138 and pfizer inc pfe rose 095 to 5328 trading volume 71 m remained 53 million below its 50day average volume of 123 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