The Dow Jones Industrial Average closed on Thursday absolutely unchanged for the day. The closing index value on Wednesday was 16,501.65, and the closing value on Thursday was also 16,501.65.
This seems very weird. One would expect at least a little change in the markets. So, we were curious to see how weird it was.
Using data from the St. Louis Fed, we looked at the Dow's daily closing prices on every trading day since May 26, 1896, the first day the Dow was calculated. And we found 197 other days when the markets were open and the day-over-day change was recorded as a 0.00.
Given that we are looking at 32,138 trading days worth of data, 198 of which (including yesterday) had no change, at a glance an estimate of the probability of getting a day with zero change is 198 ÷ 32,138, or about 0.6%.
A day with a total day over day change of 0.00 hasn't happened in a while - the last such day was Monday, December 24, 2001, when the DJIA closed at 10,035.34, the same as the previous trading day of Friday, December 21, 2001.
This drought of no change days is historically weirder than having a day with no change. We made a chart showing all of the days on which the DJIA closed at the same value, to two decimal places, as it had closed the day before. The horizontal blue lines show those days. Note the big band of white in recent years, as opposed to getting a zero change day at least occasionally before then:
Business Insider/Andy Kiersz, data from St. Louis Fed