This is my rationalization of what could be going on. Due to last nine months' bad experiences, bears are now scared of yet another rally to new highs. During the same period, no bull, who forecasted rally to new highs lost money. So, any small rally can change sentiment from bearishness to bullishness disproportionately.
http://stockcharts.com/c-sc/sc?s=$SPX&p=D&yr=0&mn=11&dy=0&i=t39436890570&r=3905&.png
In the context of May '06 decline, today's rise is possibly similar to the pause around May 14.
Edited by greenie, 06 March 2007 - 08:36 PM.