Since 2012, from Victor Niederhoffer
Since 2012 there have been 30 occasions when the eighth trading day of the month existed. And indeed the gain on the next three days was cumulatively 1.2 points, 2.4 points, and 4.2 points in actual S&P futures.
Three cheers for Yale and the super 8. ….except for all days during that period the gains the next 3 trading days were cumulatively 1.2 points, 2.4 points, and 3.6 points.