"Sell in May, go away” trend reversed under Trump with S&P 500 returning 7x more over summer months

• S&P 500 has returned 9.5% between May and October during Trump years, vs 1.3% during non-Trump years

• While markets have experienced increased volatility through tariff and aggressive foreign policy under Trump, rapid regains have led to outperformance vs 20-year average

• FTSE 100 still experiences significant “Sell in May” trend, exacerbated during Trump years

London 05 May 2026 The investment adage of “Sell in May, go away” has reversed with Donald Trump in the Oval Office, with the S&P 500 returning seven times more than normal during Trump years, according to analysis from IG. 

Returns data for the S&P 500 across the six months between 1st May and  31st October (the traditional “Sell in May” trade period) shows that the market has gained on average 9.5% under Trump versus a gain of just 1.3% across these months during non-Trump years over the past two decades, a seven-fold increase. 

Overall, the S&P 500 has significantly outperformed under Trump, with an average annual gain of 14.6% vs a gain of just 6.8% across non-Trump years over the past two decades. 

During non-Trump years over the past two decades, the S&P gained  5.5% between November and April, showing the “Sell in May” phenomenon holds true when Trump has not been in office. 

Negative impact for FTSE-100 

While Trump’s presidencies have had a surprisingly positive impact on the domestic market, particularly across the summer months, the picture is less rosy when looking at the FTSE 100. 

During non-Trump years over the past two decades, the FTSE 100 has gained on average 4.7% versus an average loss of -1.4% across Trump years. 

The “Sell in May” adage has also held true for the FTSE 100 during Trump’s presidencies so far, with an average loss between May and October of -2% compared with a gain of 0.6% between November and April. 

The trend is even more pronounced across non-Trump years over the past two decades, with an average loss between May and October of -0.3% versus a gain of 5% during the winter months.

Table showing S&P monthly returns during Trump presidency years vs 20-year average

*Data sourced from Bloomberg, April 2026

Chris Beauchamp, Chief Market Analyst UK at IG, comments: 

“The common perception of Trump’s presidency, particularly his second term, is one of market volatility, particularly in light of last year’s tariff threats and a series of unexpected foreign policy interventions since January this year. 

“However, while investors have had to ride out serious market sell-offs, rebounds have been strong, and relief moments for investors have led to rapid significant gains across US equities in particular during Trump’s time in the Oval Office, with the summer months seeing the greatest share of returns.  

“While Trump-specific trading patterns have already emerged, most notably the TACO trade (“Trump Always Chickens Out”) of buying the dip before Trump’s key trade and foreign policy deadlines, investors in US equities should also be reconsidering their summer trading habits. We may yet see a “Summer of Trump” trend emerge as investors cotton on.” 

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