The day before 9/11, the stock market processed approximately 45 times the average daily trading volume in put options (bets that a stock will fall) on American Airlines and United Airlines - the two carriers whose planes were hijacked. Simultaneously, call options (bets that a stock will rise) were placed on defense contractors - companies whose stock prices would surge after a terrorist attack. The SEC investigated the unusual trading. Their findings were classified. The 9/11 Commission addressed the put options in a single paragraph, concluding that the trades were 'consistent with legitimate trading strategies' and had 'no connection' to al-Qaeda. The Commission did not ask whether the trades had connections to anyone other than al-Qaeda. Convar - the German-Israeli firm recovering WTC hard drives - found evidence of 'suspicious financial transactions' in the hours before the attack. These findings were also classified. Someone knew. Someone traded on that knowledge. The investigation was designed to look at only one possible source - al-Qaeda - and when that source was cleared, the investigation stopped. The financial foreknowledge of 9/11 has never been publicly explained. The evidence has never been released.