Windows Mobile lost 28 percent of its smartphone market share between the third quarter of 2008 and the third quarter of 2009, according to analysis from Gartner.
According to figures released by Gartner on Thursday, Microsoft's mobile operating system had 11 percent of the global smartphone market in Q3 2008. A year later, it had 7.9 percent of the market, while the iPhone's share had risen from 12.9 percent to 17.1 percent, and RIM's share had risen from 16 percent to 20.8 percent.
Symbian's market share fell from 49.7 percent to 44.6 percent over the same period — a 10 percent drop.
The open-source Android operating system did not have any market share in Q3 2008, as it had only recently been introduced. In Q3 2009, however, it had a market share of 3.9 percent of the smartphone market. Palm's WebOS had 1.1 percent, and other Linux-based mobile operating systems had 4.7 percent.
Gartner analyst Roberta Cozza, who compiled the figures, told ZDNet UK on Friday that Windows Mobile's share in the smartphone market "continues to be challenged by other platforms".
"From one side, the market is going open source," Cozza said. "We expect that, by 2012, around 62 percent of the whole smartphone market will be open source with Symbian, Android and other Linux flavours. On the other side, they have more closed environments like Apple and RIM. Microsoft is caught in the middle. They have to think hard what they can do."
Cozza suggested that, given the strong emergence of free, open-source operating systems, Microsoft may find it difficult to demand licence fees from smartphone manufacturers. She described the recently introduced Windows Mobile 6.5 as "not a major improvement" on its predecessors, and said the OS's user interface was limited by its reliance on small icons that need stylus, rather than finger, interaction.
"[Windows Mobile] remains well positioned within the enterprise," Cozza noted, but she pointed out that 80 percent of smartphone sales are to consumers.
The analyst said Microsoft would have to come up with something "more competitive and consumer-oriented in 2010 when they announce Windows Mobile 7", but the new operating system would have to be "something pretty drastic" in order to reverse Microsoft's declining market share.
"All their licensees — HTC, Samsung, Sony Ericsson — are developing on Android," Cozza said, adding that previous licensees Palm and Motorola have both abandoned Windows Mobile.
Microsoft had not responded to a request for comment at the time of writing.