On my Stockcharts list, I've mentioned the possible formation of an inverted head & shoulder pattern possibly developing on the SP500. As noted on the chart, if this pattern holds true then the right shoulder should form if support holds at around 750. The 38% fibonacci retracement level is at about 751 so there is a good possibility for this to occur. Of course, head & shoulder patterns need confirmation to be valid which means the SP500 would need to rally past the neckline of the pattern after the shoulder has formed.