If you were a criminal mastermind about to devestate the American economy, wouldn't you do a little insider trading on the basis of that information? Short the entire stock market or something? According to the SEC, it didn't happen:
On Sept. 12, 2001, the Securities and Exchange Commission began an investigation to determine whether there was evidence that anyone who had advance knowledge of the terrorist attacks on September 11 sought to profit from that knowledge by trading in United States securities markets. In the course of that review, we did not develop any evidence suggesting that anyone who had advance knowledge of the September 11 attacks traded on the basis of that information.
Presumably Osama figured he'd be okay with just the CIA chasing him, but didn't want to mess with the SEC.
