Sell in May and go away? Historic volatility is crushing investors' favorite seasonal indicators.

Filip De Mott

Sat, May 10, 2025, 9:15 AM 4 min read

• The old motto "sell in May and go away" might not be a great guideline this year.

• Trade war, tax policy, and debt ceiling risks are skewing seasonal norms, analysts told BI.

• May tends to outperform in a postelection year.

In a market dominated by shocking headlines and policy whiplash, seasonal mottos like the old favorite, "sell in May and go away," might need a rethink.

After an unprecedented stretch of years for investors, marked by a pandemic, the highest inflation in four decades, and now a sweeping trade war, market strategists say seasonality has become much harder to predict.

"I don't think seasonal norms will be as useful in such an uncertain policy environment," Ross Mayfield, an investment strategist at Baird Wealth, told Business Insider. "The outcomes of the tariff, trade war, tax bill, and debt ceiling will have far more of an impact on returns than seasonal patterns."

It became obvious before 2025 even began that trading this year might be off-kilter. Consider that the annual "Santa Claus rally" failed to manifest in December, as earlier gains in the S&P 500 led to a rare decline that month.

Meanwhile, April — typically one of the year's three best-performing months — saw the S&P 500 fall 1.1% as tariff escalations sent volatility soaring and investors fleeing stocks.

"Sell in May and go away" is tried and true—LPL Financial says the adage can be traced to London as far back as 1776—and it reminds investors that the summer months tend to be slow for the market.

Since 1950, the six-month period between May and October has seen a mild gain of about 1.8%. This year, though, it's anyone's guess what could happen amid the trade war, a potential recession, and ongoing geopolitical strife.

"In a benign environment, you would expect to see your positive seasonal trends, but, especially after the last six weeks, who knows what we're going to be talking about," Bespoke Investment Group co-founder Paul Hickey told BI.

If historically strong months are flopping this year, then the summer may hold its own surprises, too.

"When it comes to markets, tariff uncertainty and monetary policy right now have the power to make it rain or part clouds into sunshine," Adam Turnquist, LPL Financial's chief technical strategist, wrote in late April.

To be sure, there are some positive catalysts that could occur in the "sell in May" window: trade deals are no longer just talk, and President Donald Trump's promised pro-growth policies are expected to take center stage later in the year.