SHANGHAI  James S. Chanos built one of the largest fortunes on Wall Street by foreseeing the collapse of Enron and other highflying companies whose stories were too good to be true.

Now Mr. Chanos, a wealthy hedge fund investor, is working to bust the myth of the biggest conglomerate of all: China Inc.

As most of the world bets on China to help lift the global economy out of recession, Mr. Chanos is warning that China’s hyperstimulated economy is headed for a crash, rather than the sustained boom that most economists predict. Its surging real estate sector, buoyed by a flood of speculative capital, looks like “Dubai times 1,000  or worse,” he frets. He even suspects that Beijing is cooking its books, faking, among other things, its eye-popping growth rates of more than 8 percent.

“Bubbles are best identified by credit excesses, not valuation excesses,” he said in a recent appearance on CNBC. “And there’s no bigger credit excess than in China.” He is planning a speech later this month at the University of Oxford to drive home his point.