I just learned about the “sell in May” strategy and realized that it is truly an interesting phenomenon in financial history. The story begins in 17th-century England, when wealthy investors and aristocrats would often leave London in the summer to attend famous horse racing events. From there, a proverb emerged: “Sell in May and go away, and come on back on St. Leger's Day.” About 70–80 years ago, this strategy started to become widely popular, especially in the U.S. stock market.

Looking at the data, from 1950 to 2013, the Dow Jones index shows a fairly clear pattern. From May to October, the average return is only 0.3%, while from November to April of the following year it rises to 7.5%. This figure is quite impressive, but when Barron’s conducted a deeper study over the past 30 years, they found that applying “sell in May” only produces about 0.7% higher annual returns than the average investor. And that’s before taxes and transaction costs.

But what’s interesting here is: what happens when we take this strategy to the crypto market? I reviewed crypto price data over the past 13 years (excluding 2024), and the results were quite surprising. There are 7 months with gains and 6 months with losses—meaning about 54% of the May months are up compared with 46% down. This number suggests that “sell in May” doesn’t have any special effect in crypto.

The important point I want to emphasize is: it’s not the case that you can just take a strategy from one market and apply it mechanically to another. Crypto has its own characteristics that are completely different from stocks or forex. Basic knowledge may be shared, but the way you apply it must be flexible and tailored to each market. Therefore, instead of relying on long-standing rules like “sell in May,” we need to understand the essence of each market and make decisions based on specific analysis.