GM regains crown as top-selling automaker, Toyota No. DETROIT/TOKYO (Reuters) - General Motors Co regained its title as the world's top-selling automaker from Japanese rival Toyota Motor Corp in 2011, but the U.S. company faces a challenge to stay on top this year as Toyota rebuilds its disaster-struck business. GM, bouncing back from bankruptcy only less than three years ago, said on Thursday it had sold 9.026 million vehicles globally last year, up 7.6 percent from 2010, with its Chevrolet brand setting a sales record of 4.76 million vehicles. The Detroit-based automaker's return to the top slot comes after its 2009 taxpayer-funded bankruptcy restructuring allowed it to cut its spiraling legacy costs. It also comes as Toyota's sales fell an estimated 6 percent in 2011 to 7.9 million vehicles, hit by severe production cuts following an earthquake, tsunami and nuclear crisis in Japan, and deadly floods in Thailand. The Japanese automaker is ramping up production to rebuild depleted inventory and will add output capacity in emerging markets such as Brazil and China this year. But analysts said it also faced stiffer competition as rivals step up their game. "Toyota's biggest problem is that even without the natural disasters, its sales weren't exactly growing," JP Morgan auto analyst Kohei Takahashi said. "The ranking is not that important, but they need a convincing strategy to boost their sales," he said, adding that Toyota was behind rivals such as Nissan Motor Co in rolling out small cars for emerging markets. Toyota's 2011 worldwide sales tally included listed subsidiaries Daihatsu Motors Co and Hino Motors Ltd, and it put the carmaker just behind Volkswagen AG , which sold 8.16 million vehicles last year. Toyota gave no forecast for this year for the group, but said it expected parent-only sales to jump 20 percent to a record 8.48 million vehicles in 2012. Daihatsu and Hino sold around 850,000 vehicles combined in 2011. Toyota is expected to publish a final sales tally for 2011 later this month. Shares in Toyota were up 2.9 percent on Friday morning in Tokyo, while GM ended up 1.3 percent in New York. Reporting by Deepa Seetharaman in Detroit, Chang-Ran Kim in Tokyo; Editing by Mark Bendeich