9/11. Between September 6 and 7, the Chicago Board Options Exchange recorded purchases of 4,744 "put" option contracts in UAL and 396 call options. On September 10, more trading in Chicago saw the purchase of 4,516 put options in American Airlines, the other airline involved in the hijackings, with a mere 748 call options in American purchased that day. No other airline companies had an unusual put to call ratio in the days leading up to the attacks. The 9/11 Commission concluded that all these abnormal patterns in trading were coincidental. Insurance companies saw anomalous trading activities as well. Citigroup Inc., which estimated that its Travelers Insurance unit could pay $500 million in claims from the World Trade Center attack, had about 45 times the normal volume during three trading days before the attack for options that profit, if the stock falls below $40. Citigroup shares fell $1.25 in late trading to $38.09. Morgan Stanley, which occupied 22 floors at the World Trade Center, experienced bigger-than-normal pre-attack trading of options that profited when stock prices fell. Other companies directly affected by the tragedy had similar jumps. Raytheon, a defense contractor, had an anomalously high number of call options trading on September 10. A Raytheon option that makes money, if shares are more than $25 each had 232 options contracts traded on the day before the attacks, almost six times the total number of trades that had occurred before that day. The initial options were bought through at least two brokerage firms, including NFS, a subsidiary of Fidelity Investments, and TD Waterhouse. It was estimated that the trader or traders would have realized a five million dollar profit. The Securities and Exchange Commission launched an insider trading investigation in which Osama bin Laden was a suspect after receiving information from at least one Wall Street Firm. The 9/11 Commission Report concluded that "Exhaustive investigations by the Securities and Exchange Commission, FBI, and other agencies have uncovered no evidence that anyone with advance knowledge of the attacks profited through securities transactions." The report further stated: Air-defense stand-down theory A common claim among conspiracy theorists is that the North American Aerospace Defense Command (NORAD) issued a stand down order or deliberately scrambled fighters late to allow the hijacked airplanes to reach their targets without interference. According to this theory, NORAD had the capability of locating and intercepting planes on 9/11, and its failure