Wednesday, January 18, 2006

Strength After a Down Open: What Has Followed

Wednesday's market opened down, but was up from open to close. Since January, 2004 (N = 514), we've had 52 occasions in which the market (SPY) opened lower by .3% or more. The next day, the market was up by an average of .02% (31 up, 21 down)--no real edge relative to the average change of .03% (283 up, 231 down) for the sample overall.

When we use a median split to divide the days that opened down by whether they were strong vs. weak from open to close, a pattern emerges. When the market was strong from open to close after a down open (N = 26), the next day averaged a loss of -.20% (12 up, 14 down). When the market was weak from open to close after a down open (N = 26), the next day averaged a gain of .23% (19 up, 7 down).

Interestingly, strength during the day after a weak open has not carried over to the next day. Indeed, more often than not, such strength has been reversed.