Decennial Pattern

Years ending in 5 are up years almost without exception through the entire history of the DJIA.  The two exceptions were 2005, when the DJIA fell 0.6%, and 2015 with a 2.2% drop.  Thus far in 2025, the stock market is back to its normal year 5 behavior, with a 12.5% gain through Dec. 4, 2025.  It would have to be a really bad rest of the month to spoil this year 5's record.

 This week's chart shows the Decennial Pattern for the DJIA, created by chopping the price history up into 10-year chunks of time, and averaging them together on a percentage gain basis.  It is similar in that respect to the Annual Seasonal Pattern and the 4-year Presidential Cycle Pattern.  Putting the data together this way allows us to see what typically happens over the course of each decade.

Coming up is the more problematic year 6 of the decade, which is more flat on average.  But that flat part does not start for a while, and we still have more of the uptrend seen in year 5s that continues into year 6.

This next chart shows the same comparison, but zoomed in to see the data better.  I have also adjusted the scaling so that we can get more of each of the plots on the same chart. 

The year 5 bullish effect was interrupted earlier this year when the stock market had a bit of indigestion after hearing of President Trump's tariff plans.  Investors eventually got over that, and the patterns have matched up nicely since about May 2025.  The Decennial Pattern shows that this uptrend should continue all the way to a top due ideally April 6, 2026.  That is when the sideways period of the year 6 is supposed to start.

Real life approximates the average pattern, but never duplicates it exactly.  There is no logical reason why years of the decade should matter and manifest similar behaviors, but this is something which has been going on for decades.  So there must be something to it, even if it does not make logical sense.