http://whatstrading.com/2011/04/26/putcall-ratio-leaders-as-of-301-pm-84/ (NOTE: "I can remember late 1999 and early into the new millennium, when option buyers were in a frenzy, buying up truckloads of call options on tech stocks and other momentum plays. As the put/call ratio pushed below the traditional bearish level, it seemed like these frenzied option buyers were like sheep being led to the slaughter. And sure enough, with call-relative-to-put buying volume at extreme highs, the market rolled over and began its ugly descent." http://www.investopedia.com/articles/optioninvestor/02/052102.asp )