FRANKFURT (Reuters) - BMW , the world's largest premium carmaker, posted a third-quarter gain in underlying profits that beat expectations and reaffirmed it expected to earn more money before tax than ever before this year.

Thanks to rampant demand in China, BMW's single largest market, earnings before interest and tax (EBIT) rose 13.8 percent to 2.00 billion euros ($2.56 billion) in the quarter, exceeding the 1.72 billion euros expected in a Reuters poll.

(Reporting By Christiaan Hetzner)