“Dead” investors often beat the living — at least, when it comes to investment returns.

A “dead” investor refers to an inactive trader who adopts a “buy and hold” investment strategy. This often leads to better returns than active trading, which generally incurs higher costs and taxes and stems from impulsive, emotional decision-making, experts said.

Doing nothing, it turns out, generally yields better results for the average investor than taking a more active role in one’s portfolio, according to investment experts.

The “biggest threat” to investor returns is human behavior, not government policy or company actions, said Brad Klontz, a certified financial planner and financial psychologist.

“It’s them selling [investments] when they’re in a panic state, and conversely, buying when they’re all excited,” said Klontz, the managing principal of YMW Advisors in Boulder, Colorado, and a member of CNBC’s Advisor Council.

“We are our own worst enemy, and it’s why dead investors outperform the living,” he said.

The average stock investor’s return lagged the S&P 500 stock index by 5.5 percentage points in 2023, according to DALBAR, which conducts an annual investor behavior study. (The average investor earned about 21% while the S&P 500 returned 26%, DALBAR said.)

The theme plays out over longer time horizons, too.

The average U.S. mutual fund and exchange-traded fund investor earned 6.3% per year during the decade from 2014 to 2023, according to Morningstar. However, the average fund had a 7.3% total return over that period, it found.

That gap is “significant,” wrote Jeffrey Ptak, managing director for Morningstar Research Services.

It means investors lost out on about 15% of the returns their funds generated over 10 years, he wrote. That gap is consistent with returns from earlier periods, he said.

“If you buy high and sell low, your return will lag the buy-and-hold return,” Ptak wrote. “That’s why your return fell short.”

Emotional impulses to sell during downturns or buy into certain categories when they’re peaking (think meme stocks, crypto or gold) make sense when considering human evolution, experts said.

“We’re wired to actually run with the herd,” Klontz said. “Our approach to investing is actually psychologically the absolute wrong way to invest, but we’re wired to do it that way.”

Market moves can also trigger a fight-or-flight response, said Barry Ritholtz, the chairman and chief investment officer of Ritholtz Wealth Management.

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“We evolved to survive and adapt on the savanna, and our intuition … wants us to make an immediate emotional response,” Ritholtz said. “That immediate response never has a good outcome in the financial markets.”

These behavioral mistakes can add up to major losses, experts say.

Consider a $10,000 investment in the S&P 500 from 2005 through 2024.

A buy-and-hold investor would have had almost $72,000 at the end of those 20 years, for a 10.4% average annual return, according to J.P. Morgan Asset Management. Meanwhile, missing the 10 best days in the market during that period would have more than halved the total, to $33,000, it found. So, by missing the best 20 days, an investor would have just $20,000.

(Experts do offer some caution: Be careful about holding such funds in non-retirement accounts for tax reasons.)

Routine also helps, according to Ptak. That means automating saving and investing to the extent possible, he wrote. Contributing to a 401(k) plan is a good example, he said, since workers make contributions each payroll period without thinking about it.

Meanwhile, J.P. Morgan raised its odds for a U.S. and global recession to 60%, by year end, up from 40% previously.

“Disruptive U.S. policies has been recognized as the biggest risk to the global outlook all year,” J.P. Morgan strategists said in a research note on Thursday.

Allianz’s Chief Economic Advisor Mohamed El-Erian also warned on Friday that the risk of a U.S. recession “has become uncomfortably high.”

Even though stocks took a beating on Friday, “we advise them to focus on fundamentals and what they can control, which means maintaining a strong cash reserve and discipline around cash flow so that they can stay in the market and feel confident about taking advantage of buying opportunities,” said Boneparth, a member of the CNBC Financial Advisor Council.

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Recession or not, maintaining a consistent cash flow and investment strategy is key, other experts say.

“The best way to manage these moments is to maximize your current and future selves is to block out noise that doesn’t apply to your plan,” said CFP Preston Cherry, founder and president of Concurrent Financial Planning in Green Bay, Wisconsin.

Letting emotions get in the way is one of “the greatest threats to life and money plans,” said Cherry, who is also a member of the CNBC Advisor Council.

When it comes to volatility tolerance, sharp drops in the market are to be expected, the advisors say.

“The stock market is unpredictable, but historically, there’s a trend in how the market recovers,” Cherry said.

“In years with market corrections and pullbacks, these are the worst days, which are followed by the best days,” he added.

In fact, the 10 best trading days by percentage gain for the S&P 500 over the past three decades all occurred during recessions, often in close proximity to the worst days, according to a Wells Fargo analysis published last year.

“Being out of the market and missing the best days and cycles after recessions significantly hurt portfolios in the long run,” Cherry said.

Boneparth said his clients also “know volatility and uncertainty is part of the game and, most importantly, know not to sell into chaos.”

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As U.S. markets continue to suffer steep declines in the wake of the Trump administration’s new tariff policies, you may be wondering what the next best move is when it comes to your retirement portfolio and other investments.

Behavioral finance experts warn now is the worst time to make any drastic moves.

“It is dangerous for you — unless you can read what is going to happen next in the political world, in the economic world — to make a decision,” said Meir Statman, a professor of finance at Santa Clara University.

“It is more likely to be driven by emotion and, in this case, emotion that is going to act against you rather than for you,” said Statman, who is author of the book, “A Wealth of Well-Being: A Holistic Approach to Behavioral Finance.”

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That may sound easier said than done when headlines show stocks are sliding into bear market territory while J.P. Morgan is raising the chances of a recession this year to 60% from 40%.

“When the market drops, we have sort of a herd instinct,” said Bradley Klontz, a psychologist, certified financial planner and managing principal of YMW Advisors in Boulder, Colorado. Klontz is also a member of the CNBC FA Council.

That survival instinct to run towards safety and away from danger dates back to humans’ hunter gatherer days, Klontz said. Back then, following those cues was necessary for survival.

But when it comes to investing, those impulses can backfire, he said.

“It’s an internal panic, and we’re just sort of wired to sell at the absolute worst times,” Klontz said.