This wasn’t the sort of glittering debut that Steve Ballmer had in mind when his company launched Windows Phone 8 last quarter. According to the latest numbers from comScore, Microsoft’s (MSFT) share of the United States mobile operating system market actually shrank to 2.9% in the fourth quarter of 2012, despite the high-profile debuts of Windows Phone 8 and devices such as the Nokia (NOK) Lumia 920 and the HTC (2498) Windows Phone 8X. ComScore also found that Android maintained its position as the top mobile OS in the U.S. with a market share of 53.4%, while iOS closed the gap a bit by increasing its market share from 34.3% in Q3 2012 to 36.3% in Q4 2012, aided in part by the launch of the iPhone 5.
ComScore’s latest findings do contradict recent research from Strategy Analytics showing that Microsoft last quarter had overtaken BlackBerry for the first time to become America’s No.3 mobile OS. In comScore’s latest report, BlackBerry maintains its third-place spot at 6.4% of the American smartphone market. All the same, both reports indicate that Android and iOS remained dominant in the American smartphone market while Microsoft and BlackBerry are fighting it out over single-digit shares for the first time.