What does short covering have to do with MRK not following the DOW up today after 3 down days? Its a red flag investores who sold did not rebuy MRK they went elsewhere. This has down nothing to do with short interest.
MRK was over priced up on news in a strong market. EX DIV date has passed and NO NEWS so it will stay at $46.5 the area of support on Friday. Once 2nd qtr earings announced it will drop further. Party is over! Develop some drugs or fall to $30's again.