December 2012 comScore US smart phone market share.

comScore released their December 2012 US smart phone market share report, showing that the iPhone share of the US smart phone market grew significantly in December, mostly at the expense of Blackberry.

Based on comScore's projections of ~129.5M smart phones in December 2012 (which was an increase of ~6.2M from November), we can extrapolate that, compared to November's numbers:

• Microsoft gained ~56.5K subscribers even though they lost 0.1 percentage points in market share;
• Blackberry lost ~713K subscribers and lost 0.9 percentage points in market share;
• Apple gained ~3.85M subscribers and increased 1.3 percentage points in market share;
• Google gained ~2.94M subscribers while losing 0.3 percentage points in market share.

If you look back from three months ago (September data), the Apple bounce from the iPhone 5 is clear.

Top Smartphone Platforms 3 Month Avg. Ending Dec. 2012 vs. 3 Month Avg. Ending Sep. 2012 Total U.S. Smartphone Subscribers Age 13+ Source: comScore MobiLens
	Share (%) of Smartphone Subscribers
	Sep-12	Dec-12	Point Change
Total Smartphone Subscribers	100.0%	100.0%	N/A
Google	52.5%	53.4%	0.9
Apple	34.3%	36.3%	2.0
Blackberry	8.4%	6.4%	-2.0
Microsoft	3.6%	2.9%	-0.7

Now, it's worth noting that Blackberry did itself no favors when they announced last week that their BB10 phones would not reach the US until March.  Their attrition accelerated in December -- that seems to me to be a signal that most users are not nearly as patient as Blackberry needs them to be.  And in fact, others have stated that WP has overtaken Blackberry in the US.

For Microsoft, this marks a full month of very heavy marketing of Windows 8 and Windows Phone 8, featuring their matching UIs.  And though they gained a smidgen of subscribers, the fact of the matter is, it just looks bleak for Microsoft (on both the desktop and mobile OSes).