class="mandelbrot_refrag"> Microsoft Corp co-founder Bill Gates has sold his entire stake in G4S Plc , the British security firm trying to bounce back from a series of scandals that have hurt its reputation and profits. Cascade Investment, a firm owned by Bill Gates that manages assets exclusively for the Bill & Melinda Gates Foundation Trust, had last June disclosed a stake in G4S, when its holding crossed the 3 percent threshold for the first time. A filing on May 28 showed the holding was reduced below 3 percent, and a spokesman for the Gates Foundation told Reuters on Saturday it no longer held any interest in G4S. G4S declined comment. G4S, which runs services such as cash transportation and prison management in more than 125 countries, is in the middle of overhauling its sprawling class="mandelbrot_refrag"> business , shaking up management, cutting costs, improving customer service and restructuring weak divisions to help revive its fortunes