Key Takeaways
- By analyzing past performance, economists have theorized that the stock market performs better in the six months after Oct. 31.
- Based on this observation, the Halloween investment strategy suggests buying on Nov. 1 and selling on April 30
- CCN considers whether there is any value in the advice to sell in May and go away.
In 2002, a study by economists Sven Bouman and Ben Jacobsen found that stock market returns were consistently higher in the six months between November 1 and April 30 compared to the other half of the year.
Two decades later, Bouman and Jacobsen’s paper, The Halloween Indicator, ‘Sell in May and Go Away,’ continues to inspire investment strategies based on the phenomenon they observed.
The Halloween Investment Strategy
Based on an analysis of stock prices over at least three decades, The Halloween Indicator observed a statistically significant November–April outperformance in 36 out of 37 countries assessed, with an especially pronounced effect in Europe, Australia, and Hong Kong.
While there were some years in which the pattern didn’t play out, on average, returns were found to be 4–8% higher during this period than in the summer months, even after adjusting for risk.
Based on their observation, Bouman and Jacobsen proposed a simple investment strategy: “investing in stocks from November through April and holding cash from May through October.”
In the years since The Halloween Indicator was published, a subsequent generation of economists has verified the paper’s findings and expanded on its basic investment model.
For example, Chih-Hsiang Hsu and Donald Lien suggest holding bonds during the summer months instead of cash.
Performance Over the Last Decade
To evaluate the Halloween Effect hypothesis, the table below shows where the S&P 500 Index opened on Nov. 1 and April. 31 (or the nearest weekday if the date fell on a weekend) over the last decade.
| Start |
End |
Nov 1 Open |
Apr 30 Open |
Change (pts) |
Change (%) |
| 2015-11-02 |
2016-04-29 |
2,080.76 |
2,071.82 |
-8.94 |
-0.43% |
| 2016-11-01 |
2017-04-28 |
2,128.68 |
2,393.68 |
265.00 |
12.45% |
| 2017-11-01 |
2018-04-30 |
2,583.21 |
2,682.51 |
99.30 |
3.84% |
| 2018-11-01 |
2019-04-30 |
2,717.58 |
2,937.14 |
219.56 |
8.08% |
| 2019-11-01 |
2020-04-30 |
3,050.72 |
2,930.91 |
-119.81 |
-3.93% |
| 2020-11-02 |
2021-04-30 |
3,296.20 |
4,198.10 |
901.90 |
27.36% |
| 2021-11-01 |
2022-04-29 |
4,610.62 |
4,253.75 |
-356.87 |
-7.74% |
| 2022-11-01 |
2023-04-28 |
3,901.79 |
4,129.63 |
227.84 |
5.84% |
| 2023-11-01 |
2024-04-30 |
4,201.27 |
5,103.78 |
902.51 |
21.48% |
| 2024-11-01 |
2025-04-30 |
5,723.22 |
5,499.44 |
223.78 |
-3.91% |
*Data sourced from Yahoo Finance
Looking back, the Halloween strategy delivered a positive return in six out of the past ten years, with exceptionally strong performance in 2020–2021 and 2023–2024.
So, does the S&P 500’s performance over the last decade validate the advice to sell in May and go away?
Should You Sell in May and Go Away?
Consider a $100 investment in the S&P 500 index on Nov. 2, 2015.
An investor following Bouman and Jacobsen’s suggestion to hold stocks over winter and cash the rest of the year would have grown their $100 into $175.2 by April 30, 2025.
Meanwhile, an investor who deployed a simple buy-and-hold strategy over the same period would end up with $264.3.
Applying the same methodology to other indexes* further invalidates the
Halloween investment strategy, at least in recent years. Between 2014 and 2025, the Dow Jones Industrial Average, Nasdaq 100, and FTSE All-World also favored straightforward investments over seasonal timing. The only notable exception was the FTSE 100.
The indicator breaks down most dramatically when applied to
Bitcoin, which has its own
fascinating relationship with the spooky season. A hundred dollars invested in 2015 would have grown into $2,347 by 2025 if sold and reinvested at six-month intervals. In contrast, a $100 hodler would be sitting on $28,948 after the same nine and a half years.**
Investing on Halloween
Among academics, the jury is split. While both camps acknowledge the historical trend, economists are divided over whether the average retail investor can meaningfully take advantage of the seasonal phenomenon, especially once taxes are accounted for.
In the end, the failure of the model in recent years serves as a reminder that market patterns don’t always repeat, even when history suggests they might. If the past decade is any guide, consistency, not calendar timing, remains the stronger ally of market success.
James Morales is CCN’s blockchain and crypto policy reporter. He has been working in the news media since 2020, writing about topics such as payments, banking and financial technology. These days, he likes to explore the latest blockchain innovations and the evolving landscape of global crypto regulation.
With an educational background in social anthropology and media studies, James uses his platform as a journalist to explore how new technologies work, why they matter and how they might shape our future.
