Which company do you think is the fast-rising upstart in the wearable world? Fitbit? Jawbone? None of the above, if you ask IDC. It estimates that China's Xiaomi claimed 24.6 percent of the wearable device market in the first quarter of 2015, which is no mean feat when the company didn't even start shipping its first wrist-worn gadget, the Mi Band, until the second half of last year. That still amounts to just 2.8 million devices, but it was enough to shrink the market share for virtually everyone else, including industry leader Fitbit as well as Garmin, Samsung and Jawbone. And Samsung is the only smartwatch maker on the list, we'd add. LG, Motorola, Pebble and other early entrants are lumped into the "others" group.