 The intraday chart of the SP 500 formed something of a double top at 3974 and then sagged. With less than two hours to go in trading, the index is now up 21 points to 3955, which is right about where it opened.Another trigger for the drop likely came from bonds with US 10-year yields up 8.5 bps to a session high of 3.498. This article was written by Adam Button at 