In a speech attacking her opponent, Hillary Clinton said Donald Trump cheered while the economy reeled in the aftermath of Britain’s shocking vote to leave the European Union.

"On Friday, when Britain voted to leave the European Union, he crowed from his golf course about how the disruption could end up creating higher profits for that golf course, even though, within 24 hours, Americans lost $100 billion from our 401(k)s," Clinton said in Ohio June 27. "He tried to turn a global economics challenge into an infomercial."

Trump did say last week that Brexit would benefit Turnberry, his golf course in Scotland, because a weaker pound would bring more tourists.

We wondered, though, about the other part of Clinton’s claim: that Brexit caused 50 million Americans with 401(k) retirement savings accounts to lose $100 billion in just 24 hours.

The nitty-gritty

Most 401(k) accounts are tied, at least in part, to the stock market. And the market took a pretty big hit from the British referendum, with the Dow Jones Industrial Average dropping 3.4 percent and the S&P 500 index falling 3.6 percent.

However, we couldn’t find an ongoing daily log of the total value of Americans’ 401(k)s. The Investment Company Institute puts the figure at $4.8 trillion as of March 31, 2016.

The Clinton campaign explained to us how they calculated that $100 billion figure, and experts told us the reasoning was sound.

Basically, the campaign took that March figure for the total value of all 401(k) accounts, $4.8 trillion, and calculated any growth through June 23, the day before the Brexit vote, and then the subsequent fall. They based the growth on changes in the U.S. stock market, as stocks account for about 66 percent of 401(k) assets, and fixed income, which accounts for 27 percent.

Their end result: An estimated drop of $110 billion in 401(k) assets from June 23 to June 24. Click here to see the full explanation of the campaign’s math.

The campaign approached this analysis correctly, said Wade Pfau, an expert in retirement finance and founder of RetirementResearcher.com.

"They may have even underestimated the loss by assuming all stocks are U.S. stocks. International stocks fell a lot further," he said. "But, certainly, I think their analysis is a fair and reasonable assessment about the extent of the impact on 401(k)s."

Jack VanDerHei, research director of the Employee Benefit Research Institute, also said the campaign’s calculation was a decent approximation of 401(k) losses after the Brexit vote. Running his own numbers, he came up with an estimated $104 billion loss.

Experts said, though, that average 401(k) account holders don’t need to panic.

The big picture

"The number sounds big, but it is a small percent of the total, and it is not as though this money is lost forever," Pfau said.

Four days after the Brexit vote, the U.S. stock market is starting to stabilize and creep back up. Consequently, so are the values of Americans’ 401(k)s.

Spokesmen at 401(k) providers Charles Schwab and Fidelity told us they had received many calls from account holders worried about their assets following the Brexit vote. They both said they encourage clients to stay the course and remember that saving for retirement is a long-term investment that shouldn’t be irreparably harmed by last week’s market volatility.

Generally, 401(k) accounts belonging to younger people have a higher concentration of stocks, in order to maximize growth for as long as possible. But as account holders get closer to retirement, they should reduce that concentration, effectively reducing their accounts’ exposure to market volatility, said Fidelity spokesman Mike Shamrell.

"People who have the most stock in 401(k) are those who will be impacted the most, so young people," Shamrell said. "But they’ve got the longest until they retire, so years and years and years to make it up."

Alternatively, if someone were to sell some of his or her assets amid the post-Brexit vote market turmoil, that would permanently lock in some of their losses, Pfau said.

Our ruling

After Britain’s vote to leave the European Union, "within 24 hours, Americans lost $100 billion from our 401(k)s," Clinton said.

Experts told us that Clinton’s calculation was a reasonable approximation of the loss of 401(k) assets amid market turmoil following the Brexit vote.

That being said, those losses are very likely impermanent. 401(k) accounts are long-term investments designed to withstand brief shocks like this.

The claim is accurate but needs additional information, so we rate Clinton’s claim Mostly True.