The 'Sell in May' Stock Market Rule May Be Obsolete—Here’s What It Means for Bitcoin

The long-standing market adage “Sell in May and go away” may no longer hold true. The phrase reflects a seasonal strategy suggesting stocks underperform between May and October, but recent data indicates this pattern has weakened—or even reversed.

Data Shows the ‘Sell in May’ Rule Is Fading

Bloomberg Intelligence data reveals the S&P 500 ETF (SPY) has closed the May-October period in positive territory in 25 of the last 33 years. Only one negative summer stretch has occurred in the past decade. Since SPY’s 1993 launch, cumulative returns from holding the ETF exclusively from May to October total roughly 171%—far below the 731% earned by staying invested from November to April.

Despite the seasonal performance gap, the adage that investors should automatically sell in May no longer holds weight. A Bloomberg Intelligence chart confirms SPY closed the May–October period positive in 25 of the last 33 years, returning 171% versus 731% in November–April.

Why the Old Rule May No Longer Work

The traditional logic behind “Sell in May” was that corporate earnings slow, trading volumes thin, and investors shift to cash or bonds until autumn. This strategy worked for decades in a market where institutional money moved slowly and risk appetite followed predictable seasonal patterns.

However, Bitcoin’s integration into traditional portfolio flows has altered this dynamic. Over the past two years, Bitcoin has developed direct connections to institutional investment machinery, exposing it to the same risk appetite trends driving equities.

Bitcoin’s Growing Link to Equity Markets

Data from Farside Investors shows U.S. spot Bitcoin ETFs attracted roughly $1.5 billion between April 17 and 24, bringing cumulative net inflows to approximately $58.3 billion. This structural shift has embedded Bitcoin into the same risk-on/risk-off cycles that govern traditional assets.

The Federal Reserve has also highlighted Bitcoin’s growing interconnectedness with equity markets. Its research indicates that crypto ETP bid-ask spreads are broadly comparable to those of similarly sized equity ETFs and ETPs. The Fed has further argued that monitoring NAV premiums in crypto funds provides insight into how closely crypto and equity markets have become linked.

Bitcoin’s May Setup: Fewer Seasonal Headwinds Ahead?

The case for Bitcoin entering summer with reduced headwinds hinges on the next six weeks of economic data. Key events include:

• April 28–29: Federal Reserve policy decision and Fed Chair Jerome Powell’s press conference.
• April 30: Bureau of Economic Analysis releases first-quarter GDP and March PCE data.
• May 8: April payrolls report.
• May 12: April CPI data release.
• May 20: FOMC minutes from the April meeting.
• June 16–17: Next Federal Reserve meeting.

If institutional investors refrain from de-risking in summer as they once did, Bitcoin could face fewer seasonal headwinds. This shift aligns with Bitcoin’s growing role in institutional portfolios, where risk appetite now extends year-round.

Key Takeaways

• The ‘Sell in May’ stock market rule appears outdated, with the S&P 500 posting positive May-October returns in 25 of the last 33 years.
• Bitcoin’s integration with traditional market flows may reduce its exposure to seasonal sell-offs.
• Upcoming economic data, including Fed decisions and inflation reports, will shape Bitcoin’s near-term trajectory.