Bernie Madoff's investment fund may never have executed a single trade, industry officials say, suggesting detailed statements mailed to investors each month may have been an elaborate mirage in a $50 billion fraud. An industry-run regulator for brokerage firms said ... there was no record of Madoff's investment fund placing trades through his brokerage operation. That means Madoff either placed trades through other brokerage firms, a move industry officials consider unlikely, or he was not executing trades at all. 'Our exams showed no evidence of trading on behalf of the investment advisor, no evidence of any customer statements being generated by the broker-dealer,' said Herb Perone, spokesman for the Financial Industry Regulatory Authority. Each month, Madoff sent out elaborate statements of trades conducted by his broker-dealer. There also appear to be discrepancies between monthly statements sent to investors and the actual prices at which the stocks traded on Wall Street. To some, the numbers did not add up. About 10 years ago, Harry Markopolos, then chief investment officer at Rampart Investment Management Co in Boston, asked risk management consultant Daniel diBartolomeo to run Madoff's numbers after Markopolos tried to emulate Madoff's strategy. DiBartolomeo ran regression analyses and various calculations, but failed to reconcile them. For a decade, Markopolos raised the issue with the U.S. Securities and Exchange Commission, which has come under fire in Congress in recent weeks for failing to act on Markopolos's warnings.