KnowBe4 also has the smallest float of all the stocks on this list at just 13.9 million, according to MarketWatch. That low float means any potential KnowBe4 short squeeze could be particularly volatile. iRobot Corp. ( IRBT ) Roomba maker iRobot was part of the initial 2021 short squeeze back in January, which propelled its stock from around $80 to as high as $197.40 in about three weeks. That short squeeze drove out a large number of short sellers, and iRobot's short interest dropped from 38.1% of its float on Jan. 15 to 16.9% of its float on May 28. Since late May, short sellers have returned, and iRobot's short interest is back up to 33.5% of its float. If January is any indication, another iRobot short squeeze could produce some major upside.