New York. Wall Street’s sell-off kicked back into gear on Thursday, and a US stock market rattled by the whiplash created by President Donald Trump’s tariffs and uncertainty about the economy fell sharply.

The S&P 500 tumbled 1.8 percent to resume its slide after a mini-recovery from the prior day clawed back some of its sharp drop over recent weeks. The Dow Jones Industrial Average dropped 427 points or 1 percent, and the Nasdaq composite sank 2.6 percent to finish more than 10 percent below its record set in December.

Stocks fell even though President Trump offered a one-month reprieve from his 25 percent tariffs on many goods imported from Mexico and Canada. That’s unlike the bounce stocks got the prior day from his giving a one-month exemption specifically for automakers.

All the moves keep hope alive that Trump may be using tariffs as just a tool for negotiations rather than as a permanent policy and that he may ultimately avoid a worst-case trade war that grinds down economies and sends inflation higher.

But Trump is still pressing ahead with other tariffs scheduled to take effect April 2. And the growing pile of dizzying back-and-forth moves on tariffs is only ramping up the uncertainty. It was just on Monday that Trump said there was “no room” left for negotiations to avert the tariffs on Mexico and Canada that took effect Tuesday.

“These exemptions don’t do much to resolve the general air of uncertainty,” said Yung-Yu Ma, chief investment officer at BMO Wealth Management. “Businesses will still be cautious in the current environment until a lot more of the tariff picture is clear.”

US businesses are already saying they’re confronting “chaos” because of all the uncertainty coming out of Washington while US households are bracing for higher inflation because of the tariffs, which is sapping their confidence.

“Much will depend on whether these new tariffs prove temporary or are toned down,” according to strategists at BNP Paribas. “But even if they are ultimately removed, we anticipate lasting damage to global economic activity.”

When asked whether his delays on tariffs reflected the slump in the stock market, Trump said Thursday, “I’m not even looking at the market.” He earlier in the Oval Office blamed the falling prices on “globalist countries and companies that won’t be doing as well because we’re taking back things that have been taken from us many years ago.”

Next up for Wall Street is a report coming Friday from the US Labor Department on how many workers US employers hired last month. A solid job market so far, along with the solid spending by US households that it’s allowed, have been linchpins in preventing a recession. Economists are expecting to see an acceleration in hiring for February.

Some big retailers have been offering warning signals recently about how much US consumers can keep spending.

Macy’s on Thursday reported slightly weaker revenue for the end of 2024 than analysts expected, though its profit topped expectations. It also gave a forecast for profit in 2025 that fell short of analysts’. Its shares fell 0.7 percent.

It was a similar story for Victoria’s Secret, which beat Wall Street’s fourth-quarter sales and profit forecasts but gave a revenue forecast for the upcoming year that fell short of analysts’ expectations. Its stock fell 8.2 percent.

Making things worse for the US stock market, some of its biggest stars are seeing their glow dim.

Semiconductor companies and their suppliers were particularly heavy weights, after soaring to staggering heights because of the frenzy around artificial intelligence technology.

Marvell Technology lost nearly a fifth of its value and dropped 19.8 percent even though it reported results for the latest quarter that edged past analysts’ forecasts. It also said it expects revenue growth in the current quarter of more than 60 percent from the prior year, give or take a bit.

But that wasn’t enough for investors, who have grown used to AI-related companies trouncing expectations.

The poster child of the AI boom, Nvidia, fell 5.7 percent, while Broadcom lost 6.3 percent ahead of the release of its earnings report.

AI superstars had been dominating Wall Street for years and helped it run to record after record. But those soaring performances, including a nearly 820 percent surge for Nvidia from 2023 into 2024, had critics saying prices had grown too expensive. They’re also facing threats as Chinese companies develop their own AI offerings, with DeepSeek famously saying it didn’t need to use the industry’s most expensive chips.

All told, the S&P 500 fell 104.11 points to 5,738.52. The Dow Jones Industrial Average dropped 427.51 to 42,579.08. The Nasdaq composite tumbled 483.48 to 18,069.26.