Yesterday, decliners outnumbered advancers on the NYSE by 1975 issues. The last time we had a reading that large was February 22. That was also similar to yesterday because the decline came after a rally. The following day the S&P 500 fell 8 points, followed by another 1 point decline. After that the S&P 500 rallied 13 points. The rally carried a bit further but fizzled out quickly and the market made new lows shortly thereafter.
That was a pretty textbook response to such a reading. As I mentioned earlier there is usually a weak rally after an extreme reading like we saw yesterday.