GLOBAL MARKETS-Stocks steady, investors uneasy about AI disruption

By Gregor Stuart Hunter and Amanda Cooper

SINGAPORE/LONDON, Feb 24 (Reuters) - Global shares stabilised on Tuesday, after a tumble driven by a range of factors, from uncertainty over U.S. President Donald Trump's tariff policy and geopolitical tensions to renewed worries about the upheaval to the economy from AI.

After the Supreme Court ruled Trump's emergency tariffs were unlawful on Friday, the president announced a 10% across-the-board levy, which came into effect on Tuesday. Trump later said the tariff would be 15%, but it was unclear when, or if, this would apply.

Importers could be in line for billions of dollars in refunds, while trade partners and investors alike are in the dark about where many existing tariff agreements stand.

MSCI's All-World index .MIWD000000PUS was unchanged, while in Europe, the STOXX 600 .STOXX edged up 0.2%, in sight of record highs, while U.S. stock futures ESc1, NQc1 were up 0.4%.

BEARISH ANALYSIS ON EFFECTS OF AI GETS ATTENTION

On Monday, the S&P 500 .SPX slid 1%, erasing the past week of gains, as fears over the displacement effects of AI on software and other industries pushed the Nasdaq Composite .IXIC 1.1% lower. A bearish analysis from Citrini Research on the possible risks to the global economy took a further toll on jittery investor sentiment.

The report was "getting a lot of airplay", said Tony Sycamore, market analyst at IG in Sydney. "It does align with quite a few fears which are out there."

The article, which circulated at the weekend, is one of a number of recent "think pieces" on the long-term consequences of artificial intelligence - on employment, global growth and even human existence - that have rattled investors.

In a note discussing a similar piece, Deutsche Bank strategist Jim Reid wrote: "The argument leans heavily on narrative and emotion rather than hard evidence. That doesn’t mean it will ultimately be wrong, but ... the vibes-to-substance ratio is undeniably high."

A range of software and payment stocks dropped on Wall Street on Monday. Shares of International Business Machines IBM.N plunged by more than 13% - their biggest one-day fall since late 2000 - after AI startup Anthropic said its Claude Code tool could be used to modernize a programming language run on the company's systems. IBM stock was up 0.5% in premarket trading.

The sheer scale of corporate borrowing and spending on AI has been enough to make many nervous, not least because of the outsized market weight of companies at the heart of the boom. Yet, for all the recent volatility, the S&P itself is only around 2.5% below record highs.

"None of this, so far, has delivered the knock-out blow to equity markets, where the S&P 500 has gyrated in a narrow 6,775-7,000 range since the start of the year," said ING strategist Chris Turner. "Tomorrow evening's Nvidia release might be the next big story, however."

AI chipmaker Nvidia NVDA.O, which reports earnings after the bell on Wednesday, accounts for around 8% of the entire S&P 500.

FEDEX SUES FOR REFUNDS AFTER U.S. TARIFF RULING

On Monday, Trump warned countries against backing away from recently negotiated trade deals with the U.S. after the Supreme Court tariffs ruling, saying that he would impose much higher duties on them under different trade laws.

The new tariffs are based on Section 122 of the Trade Act of 1974, causing further confusion in markets trying to come to grips with U.S. protectionist policies. Global transportation company FedEx FDX.N on Monday sued for a refund.

In currencies, the dollar was last up 0.8% at 155.89 yen and steady against the euro EUR= at $1.178.

In commodities markets, Brent crude LCOc1 traded at $71.43 per barrel, little changed on the day, while tensions continued to simmer between the U.S. and Iran. Safe-haven gold XAU= remained volatile, down 1.25% at $5,166 an ounce.