statistic number talks.

http://quantifiableedges.blogspot.com/2009/04/large-gaps-after-market-has-already.html

according to this statistic

1, if SPX gap up open over 1% that day and didnt have previous two days risen, buy at open and sell at close, over 2/3 of the trades were profitable and winners were about the same size as the losers.

2, if spx gap up open over 1% that day and had previouse two days risen, buy at open and sell at close, over 2/3 of the trades as losers. Again winners and losers are about the same size. The solid bullish tendency has switched to solidly bearish.