Stocks on Wall Street fell broadly on Thursday, pulled down again by growing worries that hefty AI investments by tech heavyweights may not pay dividends as soon as hoped.

Risk aversion also spilled into Bitcoin, which slumped to around US$65,000 and is now down nearly 50 percent from its record high above US$126,000 in October.

In Europe, the Bank of England and the European Central Bank both kept benchmark interest rates on hold as expected, as inflation pressures ease.

The euro retreated modestly against the dollar, but the British pound slid as Prime Minister Keir Starmer fights for his political life due to a storm of protest at his appointment of Peter Mandelson as ambassador to the United States, despite knowing about his close ties to convicted sex offender Jeffrey Epstein.

On equity markets, investor caution remains high after AI company Anthropic unveiled a tool that could be used by firms to carry out legal work.

The announcement on Tuesday hit numerous software stocks, underscoring investor fears that AI advances could render current technologies obsolete.

But analysts have called the sell-off indiscriminate and noted that there had already been a general shift out of tech following years of eye-watering gains.

Financial updates from Alphabet, ARM and Microsoft have fuelled that move, as questions are raised about the wisdom of pumping hundreds of billions into artificial intelligence projects with little idea about the timing of returns.

"The market continues to scream: stop spending," said Swissquote analyst Ipek Ozkardeskaya.

Big Tech companies are saying they need to spend more to meet expected AI computing demand, "but at the end of the day, investors have the last word," she added.

Most of the so-called "Magnificent Seven" equities that led stocks in 2025 faltered on Thursday. The biggest losers in the group were Microsoft and Amazon, which slumped 5.0 percent and 4.4 percent respectively.

"It'll take something to break this fever," B Riley Wealth Management's Art Hogan said of the pullback in tech, adding that a rebound might need to wait until investors conclude the selling is "overdone."

Silver prices tanked around 14 percent on Thursday as a sell-off in precious metals resumed after a brief spell of calm following massive selling when records were reached last week.

Gold, traditionally seen as a safe haven, lost more than two percent.

Oil prices dropped nearly three percent after Iran and the United States said nuclear talks would go ahead in Oman this week.

The news soothed investor concerns sparked by a report on Wednesday that the bitter foes would not meet owing to a row about the format and the venue, which sent the price of both main contracts up more than three percent.

The S&P 500 fell 1.2 percent, to 6,798, the Dow also fell 1.2 percent, to 48,908, while the tech-heavy Nasdaq fell 1.6 percent, to 22,540. (AFP)