Numerous studies have been undertaken particularly with respect to US stock markets, which confirm the relative weakness of the stock market in the summer.
So what is the status of the “sell in May” rule in other countries though?
Seasonmax examined the benchmark stock indexes of the countries with the largest market capitalization from 1970 onward, or starting from the earliest year as of which continuous price data are available.
The charts below show the chained stock market performance in nine countries during the summer months in red, during the winter months in green as well as the full year returns (=actual performance of the index) in blue.
Note: the charts are linearly scaled, as a result of which the performance patterns of the summer and winter half-year periods visually don’t appear to add up to the full year performance.
Canada: Summer Half-Year vs. Winter Half-Year
China: Summer Half-Year vs. Winter Half-Year
France: Summer Half-Year vs. Winter Half-Year
Germany: Summer Half-Year vs. Winter Half-Year
Japan: Summer Half-Year vs. Winter Half-Year
Korea: Summer Half-Year vs. Winter Half-Year
Taiwan: Summer Half-Year vs. Winter Half-Year
United Kingdom: Summer Half-Year vs. Winter Half-Year
US: Summer Half-Year vs. Winter Half-Year
In all of the markets shown here it was sensible to sell in early May – as the markets either posted losses or gains of less than one percent in the summer months in these countries. Investing in these markets during the summer was barely worth it: After all, by employing the “sell in May” strategy, one is also exposed to less risk because one is only invested half of the time.
Detailed Results By Country
The following table shows the half-year results of the eleven countries in detail. Half-year periods in which it was profitable to be invested on a risk-adjusted basis are highlighted in green. Half-year periods that generated losses are highlighted in red.
Overview Of Country Selection: Half-Year Results
Apparently a far too small number of investors is actually taking action based on their knowledge of the pattern and there is almost no arbitrage activity either. The stability and persistence of the pattern suggests that “sell in May” will continue to work in the future.
Sometimes the simple rules are the best!
InterAnalyst has been serving investors globally since 1990. Authoring hundreds financial articles and publications, thousands of trading charts to investors worldwide.