
Big gap ups that reverse in regular hours are not that common anymore, because the smart traders who anticipate the RTH reversal are already in pre market pounding on the futures while they are gapped up big. By the time the market opens, the gap up has been shrunk in size to where there is little edge. This is what happened after the State of the Union speech by Obama on Wednesday night. We traded up to 1103 on the futures but we drifted lower all night in the overnight session until the gap up was whittled down from 9 to 3 points.
Same can be said for the big gap downs. On Monday night AND Thursday night, we had mini panics in the Asian hours. On Monday night, the market went down to 1081 during Asian hours, after closing at 1092.5 in the RTH session. Usually, this means that we stay down big during afterhours and gap down big ahead of the RTH session. But the smart traders smelled the gap down buying opportunity and jumped on it, buying up futures overnight in anticipation. So a gap down of 11.5 points turned into a gap down of about 6 points. Same thing happened on Thursday night, but was even more extreme. The market closed the RTH session at 1079.25, and started weakening in Asia, down to 1071, an 8 point gap down, before staging a massive reversal and gapping up on the day by 6 points.
The competition out there is as tough as I have ever seen. There is an immense amount of statistical data that is available to the big trading institutions. They are looking for whatever edge they can get, and it is mostly coming up with mean reversion strategies that buy weakness and sell strength. That is the fundamental statistical strategy among seasoned stock market traders. They seem to be crowding out their own edge and are partly responsible for these recent unusual overnight patterns.