Why August 17th Is a Special Day and Other Interesting Stats

Today is August 17th. Did you know it happens to be one of the strongest days of the year, up 76.6% of the time? In fact, going back to 1950 only two other days are up more frequently—November 24th and December 26th. Both of those days occur near holidays, which could explain some of the upward bias. Why is August 17 unusually strong? There simply isn’t a likely answer other than it’s probably just random. Unless of course you think it’s because kids usually go back to school around now and the parents are happy.


We would like to stress we do not advise buying for one day simply based on seasonality. We do think seasonality is worth following, but for only one day it is just a fun observation.

Here are some other interesting things we are watching:

  • The S&P 500 hasn’t moved more than 1% (up or down) for 27 consecutive days, the longest streak since 32 in a row ending in late September 2014.
  • The S&P 500 has now alternated between moving higher and lower eight consecutive days. It had a streak of 11 alternating days earlier this year and another streak of eight in May. 2008 and 2005 are the only other years to have three separate streaks of eight or more consecutive alternating days going back to 1928.
  • The S&P 500 hasn’t had a 3-day losing streak for 43 consecutive days, the longest streak since 57 in a row exactly two years ago. In recent years the longest period without a 3-day losing streak was 71 days in 2010.
  • So far, the S&P 500 is up slightly in August. If it can close green, this would be six consecutive higher months for the first time since 2013. The past 11 times this has happened (back to 1983), the S&P 500 has been higher a year later all 11 times and up 14% on average.


Past performance is no guarantee of future results.
The economic forecasts set forth in the presentation may not develop as predicted.
The opinions voiced in this material are for general information only and are not intended to provide or be construed as providing specific investment advice or recommendations for any individual security.

This research material has been prepared by LPL Financial LLC.

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