9/11myths.com wrote:Perhaps the strongest challenge to this conclusion comes from Professor Allen M Poteshman from the University of Illinois at Urbana-Champaign. He decided to investigate this further, analysing market data statistically to try and assess the trades’ significance. Professor Poteshman points out several reasons to question the foreknowledge argument:
Despite the views expressed by the popular media, leading academics, and option market professionals, there is reason to question the decisiveness of the evidence that terrorists traded in the option market ahead of the September 11 attacks. One event that casts doubt on the evidence is the crash of an American Airlines plane in New York City on November 12. According to the OCC Web site, three trading days before, on November 7, the put-call ratio for options on AMR stock was 7.74. On the basis of the statements made about the links between option market activity and terrorism shortly after September 11, it would have been tempting to infer from this put-call ratio that terrorism probably was the cause of the November 12 crash. Subsequently, however, terrorism was all but ruled out. While it might be the case that an abnormally large AMR put-call ratio was observed by chance on November 7, this event certainly raises the question of whether put-call ratios as large as 7.74 are, in fact, unusual. Beyond the November 12 plane crash, an article published in Barron’s on October 8 (Arvedlund 2001) offers several additional grounds for being skeptical about the claims that it is likely that terrorists or their associates traded AMR and UAL options ahead of the September 11 attacks. For starters, the article notes that the heaviest trading in the AMR options did not occur in the cheapest, shortest-dated puts, which would have provided the largest profits to someone who knew of the coming attacks. Furthermore, an analyst had issued a “sell” recommendation on AMR during the previous week, which may have led investors to buy AMR puts. Similarly, the stock price of UAL had recently declined enough to concern technical traders who may have increased their put buying, and UAL options are heavily traded by institutions hedging their stock positions. Finally, traders making markets in the options did not raise the ask price at the time the orders arrived as they would have if they believed that the orders were based on adverse nonpublic information: the market makers did not appear to find the trading to be out of the ordinary at the time that it occurred.
http://www.business.uiuc.edu/poteshma/r ... an2006.pdfHowever, he then devises a statistical model, which he suggests is consistent with foreknowledge after all:
VI. Conclusion
Options traders, corporate managers, security analysts, exchange officials, regulators, prosecutors, policy makers, and—at times—the public at large have an interest in knowing whether unusual option trading has occurred around certain events. A prime example of such an event is the September 11 terrorist attacks, and there was indeed a great deal of speculation about whether option market activity indicated that the terrorists or their associates had traded in the days leading up to September 11 on advance knowledge of the impending attacks. This speculation, however, took place in the absence of an understanding of the relevant characteristics of option market trading.
This paper begins by developing systematic information about the distribution of option market activity. It constructs benchmark distributions for option market volume statistics that measure in different ways the extent to which non–market maker volume establishes option market positions that will be profitable if the underlying stock price rises or falls in value. The distributions of these statistics are calculated both unconditionally and when conditioning on the overall level of option activity on the underlying stock, the return and trading volume on the underlying stock, and the return on the overall market. These distributions are then used to judge whether the option market trading in AMR, UAL, the Standard and Poor’s airline index, and the S&P 500 market index in the days leading up to September 11 was, in fact, unusual.
The option market volume ratios considered do not provide evidence of unusual option market trading in the days leading up to September 11. The volume ratios, however, are constructed out of long and short put volume and long and short call volume; simply buying puts would have been the most straightforward way for someone to have traded in the option market on foreknowledge of the attacks. A measure of abnormal long put volume was also examined and seen to be at abnormally high levels in the days leading up to the attacks. Consequently, the paper concludes that there is evidence of unusual option market activity in the days leading up to September 11 that is consistent with investors trading on advance knowledge of the attacks.