FIT: Blackrock ownership history: https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001447599&type=SC+13G&dateb=&owner=exclude&count=40 https://www.sec.gov/Archives/edgar/data/1364742/000021545716004570/fitbit.inc.class.a.2015.txt Filing Date 2016-01-28 3,032,094 shares owned https://www.sec.gov/Archives/edgar/data/1364742/000021545716006006/fitbit.inc.class.a.txt Filing Date 2016-03-10 6,378,429 shares owned https://www.sec.gov/Archives/edgar/data/1364742/000021545717002283/fitbit.inc.class.a.txt Filing Date 2017-01-30 9,839,685 shares owned https://www.sec.gov/Archives/edgar/data/1364742/000021545717003002/fitbit.inc.class.a.txt Filing Date 2017-04-10 5,231,337 shares owned (They sold quite a bit) Which leads us to the current filing: So an increase from the last filing, which was a decrease from the prior one. https://www.sec.gov/Archives/edgar/data/1364742/000021545718004664/us33812l1026_013118.txt Filing Date 2018-02-01 12,861,670 shares owned. (Which is obviously a large increase)