The SPY rose 6 days in a row as of Monday. All six days have been wiped out in the last two. Looking at the 51 other such occurrences where the market has gone from a 50-day closing high to a 8-day closing low in two days, the positive expectancy going forward peaked after 5 days. A couple of weeks later, expectancy was nearly back to flat.
Here we look at a percent drop rather than an 8-day low:
Again a brief bounce that quickly peters out. I then combined the two. Only 12 occurrences but results seem notable. In this case the bounce only lasted 3 days and the expectancy beyond that turned quickly negative and stayed negative.
I ran some other tests tonight as well. So far I am not seeing anything that would lead me to believe there is a strong chance that the selloff has completely run its course.