Microsoft CEO Steve Ballmer at the company's annual Professional Developer?s Conference Thursday, Oct. 28, 2010, in Redmond, Wash.

Microsoft CEO Steve Ballmer at the company's annual Professional Developers Conference Thursday, October 28, 2010, in Redmond, Washington. Photo: AP

Influential hedge fund manager David Einhorn has called for Microsoft chief executive Steve Ballmer to step down, saying the world's largest software company's long-time leader is stuck in the past.