Stock Market Power Rankings: Microsoft Throws In the Mobile Towel

Each week, I'm ranking the biggest companies that trade on U.S. exchanges based on their size ( market capitalization), momentum (total return over the past year), and recent news. Before we get to the rankings, a quick word on a major player.

Microsoft (NASDAQ: MSFT) has been a non-factor in mobile operating systems, but this past week it wrote its own mobile-OS obituary. The software behemoth is now recommending that anyone still running Windows 10's mobile platform -- once known as Windows Phone -- switch to Apple (NASDAQ: AAPL) or Android smartphones.

Microsoft will no longer support Windows 10 mobile with free security and other updates. Mr. Softy isn't going to bow out of mobile entirely, though. It will continue to support its own apps on iOS and Android. The problem is, running a platform is a numbers game, and Microsoft-flavored smartphones just never gained traction.