Why iRobot Stock Just Rocketed 51.5%

Shares of Roomba maker iRobot (NASDAQ: IRBT) roared out of the gate Monday, climbing 51.5% through 10:45 a.m. EST in apparent delayed reaction to an endorsement from Investor's Business Daily. On Thursday last week, IBD reported that iRobot stock has improved its "relative strength" rating from 61 to 72. Already ranked No. 1 among its peers in the Household-Appliances/Hardware industry group last week, iRobot appears to be off to the races now, and unlikely to give up its title any time soon -- at least so far as IBD's RS ratings go.