shares of merck  co inc mrk slid 058 to 10492 wednesday on what proved to be an allaround favorable trading session for the stock market with the sp 500 index spx rising 142 to 402781 and the dow jones industrial average djia rising 100 to 3271760 this was the stocks second consecutive day of losses merck  co inc closed 1057 below its 52week high 11549 which the company reached on january 6th the stock underperformed when compared to some of its competitors wednesday as johnson  johnson