$MACK Merrimack Pharmaceuticals Inc (MACK) Upgraded to Hold at Zacks Investment Research MACK http://stockcharts.com/c-sc/sc?s=mack&p=D&b=5&g=0&i=p24597972749&r=1363673449596%5B/img%5D https://www.americanbankingnews.com/2017/05/15/merrimack-pharmaceuticals-inc-mack-upgraded-to-hold-at-zacks-investment-research.html