Shockwaves reverberated through Wall Street on Thursday after a new, sweeping round of U.S. tariffs upended economic forecasts and intensified worries about global growth, sending stock markets tumbling.

The S&P 500 fell almost 5% Thursday, its worst showing since June 2020 at the height of the coronavirus pandemic. The news had already rattled Asian and European markets earlier in the day.

The Dow Jones industrial average dropped 1,679 points, or 4%, and the Nasdaq composite tumbled 6%.

The tremors spread further than just stocks. Measures of inflation expectations jumped, intensifying fears of an economic slowdown and sending the dollar down against every currency of the group of 10 nations. Investors rushed to the safety of government debt.

The turmoil erupted after President Donald Trump announced on Wednesday a new 10% baseline tariff on all imports as well as additional, country-specific taxes on goods from a host of other countries.

“Trump’s tariff plan probably represents a shift for markets to quickly move from max uncertainty to max pessimism,” said Jeff Buchbinder, the chief equity strategist for LPL Financial. Other analysts and investors simply expressed bewilderment.

Everything from crude oil to Big Tech stocks fell. Some of the worst hits walloped smaller U.S. companies, and the Russell 2000 index of smaller stocks dropped 6.6% to pull more than 20% below its record.

Richfield-based Best Buy fell 17.8% because the electronics that it sells are made all over the world. Minneapolis-based Target tumbled 10.9%.

Apple fell more than 9%, Amazon dropped 9% and shares in Nvidia moved nearly 8% lower.

In Europe, shares of Puma and Adidas tumbled alongside the stock of Pandora, a Danish jewelry company that makes its products in Thailand, which fell 10.7%.

Investors flocked to government debt as a haven. The yield on the 10-year U.S. Treasury bond, which moves inversely to prices, fell to 4.04%, its lowest since October.

All told, the S&P 500 fell. 274.45 points to 5,396.52 The Dow sank 1,679.39 to 40,545.93, and the Nasdaq composite tumbled 1,050.44 to 16,550.61.

— News services

Stellantis to halt Mexico, Canada plants

Automaker Stellantis is temporarily halting production at a plant in Canada and a plant in Mexico shortly after President Donald Trump announced a 25% tariff on imported vehicles. The move will result in the temporary layoff of 900 U.S. employees.

Stellantis, which owns car brands like Jeep, Citroën and Ram, said Thursday it will be temporarily pausing production at the Windsor assembly plant in Canada for the weeks of April 7 and 14. Operations will resume at the facility the week of April 21.

The company will also be temporarily pausing production at the Toluca assembly plant in Mexico for the month of April, starting on April 7.

Jobless claims inch down in past week

The number of Americans seeking unemployment benefits fell modestly last week, remaining within the same range of recent years.

Jobless claim filings fell by 6,000 to 219,000 for the week ending March 29, the Labor Department said Thursday. That’s less than the 226,000 new applications analysts forecast.

Weekly applications for jobless benefits are considered a proxy for layoffs, and have remained mostly in a range between 200,000 and 250,000 for the past few years.

16 possible U.S. data center sites named

The U.S. Department of Energy said it has identified 16 federal sites, including storied nuclear research laboratories such as Los Alamos, N.M., where tech companies could build data centers in a push to accelerate commercial development of artificial intelligence technology.

The move follows an executive order signed in January by outgoing President Joe Biden that sought to remove hurdles for AI data center expansion in the U.S. while also encouraging those data centers, which require large amounts of electricity, to be powered with renewable energy.

While President Donald Trump has since sought to erase most of Biden’s signature AI policies, he made clear after returning to the White House that he had no interest in rescinding Biden’s data center order.

— From news services