Microsoft (NASDAQ:MSFT) is a multi-national software manufacturer. Its Windows Phone mobile operating system is the successor to Windows Mobile; however, the two OS are not backwards compatible. Windows Phone 8 is the latest version of the Windows Phone platform and launched in October 2012. Nokia's (NYSE:NOK) Lumia devices run the Windows Phone platform.

Microsoft currently claims a 3 percent market share of the U.S. smartphone subscriber market, according to comScore data from April 2013. Microsoft's current CEO is Steve Ballmer.