Wall Street has its worst day in a month on worries about AI stocks and interest rates

The U.S. stock market sank to its worst day in a month and its second-worst since April.

The S&P 500 fell 1.7% Thursday and pulled further from its all-time high set late last month. The Dow Jones Industrial Average fell nearly 800 points from its own record set the day before, while the Nasdaq composite lost 2.3%.

Nvidia and other AI superstar stocks dragged the market lower amid continued worries that their prices had shot too high. Most other stocks on Wall Street also fell as traders questioned whether the coming cuts to interest rates that they’ve been banking on will actually happen.

Questions have been rising about how much further such AI darlings can go following their already spectacular gains. At the start of this month, Palantir was sporting a stunning rise of nearly 174% for the year so far, for example.

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The Fed's job became more difficult recently because of the U.S. government's six-week shutdown, which delayed many updates on the job market and other signals about the economy. That left it less certain about whether the slowing job market or high inflation is the bigger threat.

The stock market mostly rose through the U.S. government's shutdown, as it has often done historically, but Wall Street is bracing for potential swings as the government gets back to releasing those updates. The fear is that the data could persuade the Fed to halt its cuts to rates.

The “looming data deluge may spur additional volatility in the coming weeks,” according to Doug Beath, global equity strategist at Wells Fargo Investment Institute.

On Wall Street, The Walt Disney Co. helped lead the market lower after falling 8.1%. The entertainment giant reported profit for the latest quarter that topped analysts’ expectations, but its revenue fell short.

That helped offset a jump of 4.2% for Cisco Systems after the tech giant delivered profit and revenue that were bigger than analysts estimated.

Another one of the relatively few stocks to rise was Berkshire Hathaway, the company run by famed investor Warren Buffett. He is known for loving bargains and won't buy stocks when they look too expensive. Berkshire Hathaway rose 1.9%.

In the bond market, Treasury yields pushed higher, which put downward pressure on prices for stocks and other investments.

The yield on the 10-year Treasury rose to 4.11% from 4.08% late Wednesday.

In stock markets abroad, indexes sagged in Europe following modest gains in Asia.

Tokyo's Nikkei 225 index rose 0.4%, even as Japanese tech giant SoftBank Group lost another 3.4%. It’s been struggling since it said earlier this week that it had sold all of its $5.8 billion stake in Nvidia.