After two positive days, all three indices declined on Wednesday. While the DJIA was off by just a tiny fraction, the NASDAQ lost -.88 percent, and the S&P500 dipped -.24 percent.
The historical results, since January 2000, are an equal number of advances and declines for the next trading day, with the median gain and losses also about the same:
DJIA Median -.66 percent and +.70 percent,
NASDAQ Median -.95 percent and +.95 percent,
S&P 500 -.71 percent and +.67 percent.