“Buy in May and Go Away, But Remember to Be Back in September”: A Historical Overview and Its Relevance Today

The phrase “Buy in May and Go Away, but remember to be back in September” is a derivative of the old stock market adage, “Sell in May and go away.” The latter part, about returning in September, is a modern extension. It is a shorthand for a seasonal trading pattern that investors have observed over the years in equity markets. While these sayings are part of traditional investment folklore, their efficacy and relevance in today’s fast-paced, globally interconnected financial markets are subjects of ongoing debate.


The origins of the “Sell in May and go away” saying can be traced back to the London financial community. Initially, it was “Sell in May and go away, do not return until St. Leger’s Day.” St. Leger’s Day refers to the St. Leger’s Stakes, a notable horse race in England, usually held in mid-September. The adage reflects the seasonal behaviors of London’s financial brokers and bankers, who would often leave the city for the summer, returning for the race, reducing market activity during these months.

The strategy implies that the stock market’s performance is typically weaker between May and October than between November and April. So, selling stocks in May and buying them back in November theoretically maximises returns.

Evolution: Return in September

The variant “Buy in May and go away, but remember to be back in September” reinterprets the original saying. It suggests buying stocks in May, leaving the portfolio alone over the summer, then actively managing investments from September onwards. This modification might be due to variations in market performance patterns over time.

Relevance Today

In assessing the relevance of these sayings in 2023, it’s crucial to consider the dynamic changes in the financial markets over the past decades. For one, we live in an era where market sentiment is swayed by myriad global factors, such as geopolitical events, technological breakthroughs, and unexpected black swan events like the COVID-19 pandemic.

Further, the rise of quantitative and algorithmic trading, where investment decisions are made based on sophisticated mathematical models, has significantly changed the landscape of the stock market. These models consider several variables and are agnostic to the month of the year.

Many studies and analyses conducted over the past years have shown inconsistent results regarding the “Sell in May” strategy. Some studies confirm its validity, while others refute it, underscoring the complexities and variabilities of market performance.

A 2023 Perspective

As of 2023, while seasonal patterns in the stock market can still be observed, they shouldn’t be the primary driver of investment decisions. More than ever, a comprehensive, well-diversified investment strategy that considers various factors, including but not limited to company fundamentals, macroeconomic indicators, and geopolitical developments, is advisable.

The adage also doesn’t account for transaction costs. Selling in May and buying back later would incur additional costs that could erode potential profits.

Furthermore, it encourages a form of market timing, predicting when to buy or sell stocks, which is generally not recommended for average investors.

Lastly, the saying assumes that all markets behave the same way, which is not the case. Different markets around the world might show varying seasonal trends based on factors unique to each region.


“Buy in May and go away, but remember to be back in September,” and its original counterpart, encapsulate long-observed seasonal trends in the stock market. However, in the face of the modern global financial environment’s complexity and interconnectivity, the wisdom these sayings offer should be considered with caution. The most effective investment strategies are those that adapt to the investor’s specific needs and market realities rather than those tied to calendar traditions. As always, the best advice is to remain informed, diversify, and think long term.

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