Merck&Co fell by 3.08% to trade at $83.46 by 15:57 (19:57 GMT) on Wednesday on the NYSE exchange.
The volume of Merck&Co shares traded since the start of the session was 8.09M. Merck&Co has traded in a range of $83.39 to $85.83 on the day.
The stock has traded at $86.7900 at its highest and $82.8000 at its lowest during the past seven days.
