“The Republican Party will use its best efforts to eliminate Daylight Saving Time, which has a small but strong constituency, but shouldn’t!” he wrote in a post on his social media platform, Truth Social. “Daylight Saving Time is inconvenient, and very costly to our Nation.”

Originally introduced as an energy-saving measure in both World Wars, studies have cast doubt on whether the extra hour of daylight is worth the headache. Changing the clocks regularly draws criticism, and, earlier this month, Tesla CEO Elon Musk and entrepreneur Vivek Ramaswamy said they want to target the practice as the leaders of Trump’s semiofficial Department of Government Efficiency.

It’s unclear if Trump, whose team did not respond to a request for comment, favors making daylight saving time permanent—which would result in more light in the afternoon—or keeping the country on standard time, which would mean more morning light. In 2022, Florida Sen. Marco Rubio, whom Trump has nominated to lead the State Department, cosponsored the Sunshine Protection Act, a now-stalled bipartisan bill that would have made daylight saving time permanent. Meanwhile, most health experts have the opposite preference.

The end of clock-shifting, meanwhile, would deliver real economic fallout for certain industries. If the Rubio version of the plan to keep the country on daylight saving time goes forward, here are the winners and losers.

Winners

Tourism

The equation is simple: More afternoon and evening daylight equals more visitors at monuments and other attractions. Speaking to National Geographic in 2011, Kurt Janson, policy director at the U.K.’s Tourism Alliance, said Britain’s tourism industry could experience a boost of £3.5 billion (then about $5.6 billion) per year if daylight saving time became permanent, citing data from a British think tank called the Policy Studies Institute. “In a nutshell, it would extend the spring and fall shoulder seasons for the tourism industry,” Janson said.

Retail

There’s a similar argument to be made for convenience retailers, who say customers also spend more when the sun stays out longer. Two years ago, an industry rep told a House committee that stores logged increased spending through daylight saving time. Meanwhile, a 2016 study from the JPMorgan Chase Institute found that consumer spending dropped 2.2% to 4.9%, depending on the city surveyed, after the switch back to standard time.

The stock market

From 2007 to 2022, the S&P 500 gained 7.5% on average during daylight saving time and just 2% for the rest of the year, according to an analysis from Bespoke Investment Group cited by Barron’s. Correlation does not equal causation, of course, but it seems Wall Street traders—like many Americans—don’t enjoy losing an hour of sleep when the clocks change. Researchers at the business schools of Kentucky, Georgia State, Arkansas, and Emory recently found capital markets participants are slower to respond to earnings news during the week after clocks “spring forward” on Mar. 10.

Losers

Your health

Medical groups like the American Medical Association and American Academy of Sleep Medicine say standard time better aligns with our circadian rhythm, or the natural rhythm of our bodies and minds every 24 hours. As the British Medical Journal noted last year, a string of studies suggests daylight saving time has been linked to an increase in heart attacks, strokes, and other health issues.

An updated analysis from Chmura Economics & Analytics estimated the annual economic cost of daylight saving time at $672 million, including roughly $375 million owing to increased heart attacks, $252 million from more strokes, $18 million from additional workplace injuries, and $27 million from an uptick in traffic accidents.

Morning commuters

The U.S. has made daylight saving time permanent before, with President Nixon signing the bill into law in December 1973 amid the oil crisis. During the winter, however, Americans soon soured on getting to work or school in the dark. Incidents of schoolchildren being struck and killed by vehicles became national news.

That included eight deaths in Florida, prompting the state’s governor, Reubin Askew, to ask Congress to repeal the measure. By October, President Ford had signed a bill to put the U.S. back on standard time for four months of the year. A switch to permanent daylight saving time would bring renewed grumbling from commuters and parents, especially those at the western edge of large time zones.