Investors can get swept away by the fear or euphoria of the recent past — and it often costs them financially.

“Recency bias” is the tendency to put too much emphasis on recent events, like a stock-market rout or the meteoric rise of bitcoin or a meme stock like GameStop, for example.

Investor choices are guided by these short-term events — which may be counter to their best interests, as is often the case when selling stocks in a panic.

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Recency bias is akin to a common yet illogical human impulse, such as watching Steven Spielberg’s classic summer blockbuster “Jaws,” a 1975 thriller about a Great White shark whose diet revolves more around humans than marine life, and then being afraid of the water.

“Would you want to go for a long ocean swim after watching ‘Jaws’? Probably not, even though the actual risk of being attacked by a shark is infinitesimally small,” wrote Omar Aguilar, CEO and chief investment officer at Schwab Asset Management.

The financial services sector was among the top performers of the S&P 500 Index in 2019, when it yielded a 32% annual return. Investors who chased that performance and subsequently bought a bunch of financial services stocks “may have been disappointed” when the sector’s returns fell by 2% in 2020 — a year when the S&P 500 had a positive 18% return, Aguilar said.

Among other examples posed by financial experts: tilting a portfolio more heavily toward U.S. stocks after a string of underwhelming performance in international stocks, and overreliance on a mutual fund’s recent performance history to guide a buying decision.

“Short-term market moves caused by recency bias can sap long-term results, making it more difficult for clients to reach their financial goals,” he said.

The concept generally boils down to fear of loss or a “fear of missing out” — or, FOMO — based on market behavior, said Charlie Fitzgerald III, an Orlando, Florida-based certified financial planner.

Acting on that impulse is akin to timing the investment markets, which is never a good idea; it often leads to buying high and selling low, he said.

“People need to understand that recency bias is normal, and it’s hard-wired,” said Fitzgerald, a principal and founding member of Moisand Fitzgerald Tamayo. “It’s a survival instinct.”

It’s like a bee sting, he said.

“If I get stung by a bee once or twice, I’m not going to go there again,” Fitzgerald said. “The recent experience can override all logic.”

Investors are most vulnerable to recency bias, he said, when on the precipice of a major life change like retirement, when market gyrations may seem especially scary.