A jump in UAL (United Airlines) put options 90 times (not 90 percent) above normal between September 6 and September 10, and 285 times higher than average on the Thursday before the attack.
-- CBS News, September 26
A jump in American Airlines put options 60 times (not 60 percent) above normal on the day before the attacks.
-- CBS News, September 26
No similar trading occurred on any other airlines
-- Bloomberg Business Report, the Institute for Counterterrorism (ICT), Herzliyya, Israel [citing data from the CBOE] 3
Morgan Stanley saw, between September 7 and September 10, an increase of 27 times (not 27 percent) in the purchase of put options on its shares. 4
Merrill-Lynch saw a jump of more than 12 times the normal level of put options in the four trading days before the attacks. 5

The Wall Street Journal reported on October 2 that the ongoing investigation by the SEC into suspicious stock trades had been joined by a Secret Service probe into an unusually high volume of five-year US Treasury note purchases prior to the attacks. The Treasury note transactions included a single $5 billion trade. As the Journal explained: "Five-year Treasury notes are among the best investments in the event of a world crisis, especially one that hits the US. The notes are prized for their safety and their backing by the US government, and usually rally when investors flee riskier investments, such as stocks." The value of these notes, the Journal pointed out, has risen sharply since the events of September 11. 15

http://www.wsws.org/en/articles/2001/10/bond-o05.html

http://www.cbsnews.com/stories/2001/09/19/eveningnews/main311834.shtml

http://www.orms-today.org/orms-6-04/predict.html

http://hindu.com/2001/10/01/stories/06010006.htm