Latest guesstimate pegs Apple Watch at 3.6M units shipped last quarter

IDC's latest Worldwide Quarterly Wearable Device Tracker suggests that 3.6 million Apple Watch units shipped last quarter, giving it a 19.9 percent share of units worldwide. IDC claims that was second only to Fitbit, which it estimates shipped 4.4 million units, for a 24.3 percent share.

The only other wearable device maker to crack the million-unit mark, IDC's research suggests, was Xiaomi, which is said to have shipped 3.1 million units, good for third place. IDC's estimates place Garmin in fourth with 700,000 devices shipped, and Samsung in fifth with just 600,000 units.

IDC projects that total wearable shipments reached 18.1 million units last quarter, up a massive 223.2 percent from the same period a year prior.

"Anytime Apple enters a new market, not only does it draw attention to itself, but to the market as a whole," said Ramon Llamas, research manager for IDC's Wearables team. "Its participation benefits multiple players and platforms within the wearables ecosystem, and ultimately drives total volumes higher. Apple also forces other vendors - especially those that have been part of this market for multiple quarters - to re-evaluate their products and experiences.

"Fairly or not, Apple will become the stick against which other wearables are measured, and competing vendors need to stay current or ahead of Apple. Now that Apple is officially a part of the wearables market, everyone will be watching to see what other wearable devices it decides to launch, such as smart glasses or hearables."

Any such numbers should be met with some level of skepticism, however, as Apple itself has not revealed any specific sales or shipment data of the Apple Watch.

Further complicating matters is the fact that the Apple Watch was only available at Apple's own stores until earlier this month when it debuted at Best Buy —  after the June quarter covered by IDC's research. That means the only company with any concrete idea of the watch's performance thus far would be Apple itself.

For its part, IDC has said that its "Tracker" products rely on proprietary tools and research processes. Detailed findings from IDC's research can be obtained by purchasing the report from the company.

Though Apple hasn't given specific sales figures, the company did make an effort to combat erroneous research that suggested sales of the Apple Watch were "collapsing" post-launch. Apple Chief Executive Tim Cook said last month that the device had actually posted its best monthly performance to date in June.

Sales estimates, however, have been all over the map: Slice Intelligence put first-quarter sales at 2.79 million, Canalys estimated 4.2 million, and Bloomberg forecast sales at 1.9 million.

Many of the forecasts have ignored context from Apple itself, as the company revealed last month that the Apple Watch outsold the first-generation iPad through its first nine weeks. Sales of the first iPad were announced in 2010, when it was revealed that the device had reached 3 million on day 80.