By Michael LiedtkeSAN FRANCISCO (AP) - Yahoo! ( YHOO) co-founder Jerry Yang is stepping down as CEO, ending a rocky reign marked by his refusal to sell the Internet company to Microsoft ( MSFT) for $47.5 billion -- more than triple Yahoo's current market value. The change in command announced Monday won't be completed until Yahoo finds his replacement. The Sunnyvale, Calif.-based company said it is interviewing candidates inside and outside Yahoo! in a search led by its chairman, Roy Bostock, and the executive recruitment firm Heidrick & Struggles. "Jerry and the board have had an ongoing dialogue about succession timing, and we all agree that now is the right time to make the transition to a new CEO who can take the company to the next level," Bostock said. Yang, who started working on Yahoo! with Stanford University classmate David Filo in 1994, will revert to "Chief Yahoo," a titular role he filled before replacing former movie studio boss Terry Semel as CEO in June 2007. He will also remain on Yahoo!'s board. "I will continue to focus on global strategy and to do everything I can to help Yahoo! realize its full potential and enhance its leading culture of technology and product excellence and innovation," Yang said in a statement. Sue Decker, Yahoo!'s president, is expected to be among the candidates to succeed Yang, although she has been an integral part of the management team that has exasperated the company's shareholders. Dan Rosensweig, who resigned as Yahoo!'s chief operating officer, also could be lured back as CEO, or the board could turn to one of its own directors, such as former Viacom ( VIA) CEO Frank Biondi or former Nextel CEO John Chapple.