Wall Street stocks tumbled Thursday on mounting worries over the economic impact of U.S. President Donald Trump's multi-front tariff war.

All three major U.S. stock indexes suffered steep losses, forfeiting much of the previous session's gains as growing concerns over the escalating Washington-Beijing trade face-off dampened optimism over upbeat economic data and U.S.-Europe trade negotiations.

According to preliminary data, the S&P 500 lost 189.79 points, or 3.45%, to end at 5,267.11 points, while the Nasdaq Composite lost 737.66 points, or 4.31%, to 16,387.31. The Dow Jones Industrial Average fell 1,029.51 points, or 2.54%, to 39,578.94.

After Trump announced a 90-day tariff reprieve on Wednesday, the S&P 500 surged 9.5%, the largest one-day percentage jump since October 2008. The tech-heavy Nasdaq soared 12.2%, notching its second-biggest daily gain on record.

Following the whipsaw of Wednesday's bounce and Thursday's selloff, the S&P 500 remained well below levels before the reciprocal tariffs were announced last week.

"Investors are still uncomfortable with it, because they don't know what the end game is," said Paul Nolte, senior wealth advisor at Murphy & Sylvest in Elmhurst, Illinois. "I think what we're seeing, still, is investor concern about tariffs and that is pretty much front and center for everything."

The Labor Department's Consumer Price Index report showed the prices consumers pay for a basket of goods unexpectedly edged lower in March, with core price growth cooling down 2.8% year-on-year, coming within one percentage point of the Federal Reserve's 2% inflation target.

But the Fed's path forward, in light of ongoing trade negotiations, is less clear.

Fed Governor Michelle Bowman said on Thursday that while the U.S. economy remains strong, the effects of Trump's trade policies are unclear, while Chicago Fed President Austan Goolsbee said rate cuts could resume once the uncertainties surrounding trade policy is resolved.

In response to Trump's 90-day tariff pause, the European Union will delay retaliatory levies on American goods as countries within the bloc scramble to reach trade deals with Washington, said European Commission chief Ursula von der Leyen.</p> <p>But the trade war with Beijing persists, with China vowing to "follow through to the end" if the U.S. does not let up.

The CBOE Market Volatility Index, often called the "fear index," remained elevated.

"It's hard for investors to feel comfortable about buying stocks with volatility so high," Nolte added.

Big Tech came under pressure once again, with each of the so-called Magnificent Seven group of artificial intelligence-related momentum ending with steep losses.

CarMax slid after the used-car retailer missed fourth-quarter profit expectations.

First-quarter earnings season kicks off on Friday with big banks, including JPMorgan Chase, Morgan Stanley and Wells Fargo due to report.