Merck&Co fell by 3.07% to trade at $83.92 by 10:07 (14:07 GMT) on Monday on the NYSE exchange.
The volume of Merck&Co shares traded since the start of the session was 1.33M. Merck&Co has traded in a range of $83.91 to $86.47 on the day.
The stock has traded at $87.3500 at its highest and $83.8700 at its lowest during the past seven days.
