shares of biogen inc biib sank 014 to 29395 thursday on what proved to be an allaround mixed trading session for the stock market with the sp 500 index spx rising 037 to 438189 and the dow jones industrial average djia falling 001 to 3394671 biogen inc closed 2581 short of its 52week high 31976 which the company reached on june 12th the stock demonstrated a mixed performance when compared to some of its competitors thursday as johnson  johnson jnj rose 106 to 16562 and pfizer inc pfe fell 044 to 3873 trading volume 905577 remained 132956 below its 50day average volume of 10 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