Day of the Month Seasonality Part 2: DAX, CAC 40, FTSE 100

In part 1 of the series I showed the impressive predictive power of day of the month seasonality effects in US equity markets. In this post I will apply the same type of analysis to three European markets: Germany (using the DAX index), France (using the CAC 40 index), and the U.K. (using the FTSE 100 index). Once again I must note that day of the month effects by themselves do not constitute a trading strategy, but I believe that the impressive returns predictability can be used to enhance other trading approaches, both systematic and discretionary.


The methodology:

The European indices have a far shorter history than the US ones, so we need to limit the look-back period in order to get a useful sample size. As such, I have slightly modified the approach to use less data in the early parts of the sample.

  1. Standardize every month to 21 trading days; round to the nearest integer when the number of days in a month is different.
  2. Start by using the last 2500 days; keep increasing the sample size until you reach 5000 days. After that use a moving window of the last 5000 days of daily returns and estimate the average return on every (standardized) day of the month.
  3. Rank the days by their past returns. If the next day is in the top 6, buy on close and sell on the next close.
  4. Move forward by one trading day and repeat from step 2.

The results:


The equity curves:

DAX day of the month seasonality results

And the statistics:

DAX stats


CAC 40:

The equity curve:

CAC 40 day of the month seasonality results

And the statistics:

cac 40 stats


FTSE 100:

The equity curves:

FTSE 100 day of the month seasonality results

And the statistics:

ftse100 stats



daily returns calendar

One of the results that stands out is that the 15th day of the month seems to be absolutely terrible in every market. This is doubly peculiar because while the best days seem to be different for every market, the worst ones are consistent across the board. I would love to hear some theories about this.

In any case, day of the month seasonality effects are incredibly powerful in European markets as well. They’ve managed to provide positive returns in essentially all market environments. The fact that the best days occur on different parts of the month depending on which market you look at is amazing: it means there are more opportunities out there to exploit if you’ve got capital lying around.

In the next (and for now, final) part of the series, I will look how these seasonality effects hold up in Asian markets.