Most people here know this poster, he always comes in at the close and says "you know the drill, by the cash close, sell the cash open" Well I decided to end this once and for all, and I did a backtest all the way back to Jan 1950 on the S&P. Number of gaps-6070 Number of gap downs-2998 Number of gap ups-3072 Probability of buying the close and selling at a higher open? 50.6% Average gap (Ups and Downs included)= .009% There you go, nail in the coffin, a worthless strategy
The trading day in CA ends about lunchtime for many workers. If one is working full time and has a working strategy for guessing the direction of an expected gap one can trade without interfering with work duties. Put in an entry order at lunchtime and exit the following morning on the gap + noise...