The remarks came from "a prominent chief executive", according to the site. Gates left Microsoft to focus on philanthropy in June 2008, though he is still the chairman of the board and the company's largest shareholder. Right now, Gates is focused on nuclear power plants in China, but there are a couple of factors that could send him back to Redmond desk. One would be the Microsoft stock value. Earlier this year, activist investor David Einhorn of Greenlight Capital likened Ballmer to a weight dragging down the company's share price.