AI-linked stocks tumble after tech leaders call for slowdown in AI development

AI-linked stocks tumbled on Monday after the bosses of Anthropic, OpenAI and SpaceX called for a slowdown in AI “reckless” development, citing fears the technology could soon run out of control.

Shares in the semiconductor designer Nvidia – the world’s most valuable company – were down 3.3% by market closing in New York City, while Advanced Micro Devices (AMD) slid 4% and Micron Technology and Sandisk shares slumped by 5%. The tech-heavy Nasdaq index fund was down 0.5% by the end of the day.

The sell-off came after the chief executive of Anthropic, Dario Amodei, appealed at the weekend for the AI industry to “slow down”.

However, Donald Trump dismissed calls to increase controls on AI as a “sick conspiracy”.

In a social media post on Monday, the president wrote: “The only control or ‘guardrails’ that AI needs is a STRONG AND SMART (High IQ!) PRESIDENT, and the USA has that, in spades!”

The president added that his administration had “stopped AI ‘people’ from doing bad, or potentially bad, ‘things,’ like Dario (Anthropic!)”.

“There is a SICK conspiracy going on against AI and Data Centers, and the only one that is happy about it is China. WHOEVER WINS AI, WINS!”, he wrote.

Trump offered a similar assessment when he called Nvidia chief, Jensen Huang, while the executive was on stage at an AI conference in California on Monday.

“It’s a hoax,” Trump said via speaker phone to the audience. “The robots are not going to be taking over the world. That’s not going to happen.”

Shares in SoftBank, a Japanese investor that is a big backer of OpenAI, slumped 13%, while the South Korean Kospi stock index, which relies heavily on chipmakers that supply AI companies, dropped by 3%.

Shares in the big global microchip supplier Taiwan Semiconductor Manufacturing Company dropped 1.2%.

In Europe, shares in the Dutch tech manufacturer ASML, Europe’s biggest company by value and an important supplier for the semiconductor industry, slumped by 6%.

There was, however, a rally in shares that have been threatened by the rise of AI, including the advertising group WPP, which rose by 5% in London, and the analytics business Relx, which was also up 5%. The latter had suffered a sharp fall earlier this year after Anthropic launched a suite of new data and automation tools.

Amodei has said that “building too fast is reckless”, warning that a swarm of AI agents could cause hundreds of billions of dollars of damage by “taking over the entire internet” in future.

His claims have been disputed by some experts, but on Monday investors began to price in a slowdown that would make it harder for the industry to pay for hundreds of billions of dollar in investments in AI infrastructure.

The OpenAI CEO, Sam Altman, the Google DeepMind chief, Demis Hassabis, and SpaceX boss, Elon Musk, all posted support for Amodei’s essay on slowing AI development, titled “We Must Pace the Frontier”.

Altman added that he would match Amodei’s commitment to embedding outside evaluators within his company to verify safety practices.

Fears continue to grow over the rapid pace and lack of regulation in AI development. On Monday, a cross-party group of UK MPs and peers identified a series of human rights risks posed by AI, arguing that no country in the world had laws sufficient to contain them.

Meanwhile, China’s top intelligence official warned that the use of AI by adversaries could pose a risk to the country’s political and social security.

Chen Yixin wrote in a government outlet on Sunday that advanced US models such as Anthropic’s Mythos and OpenAI’s GPT-5.5-Cyber could pose serious risks to Beijing’s critical information ​infrastructure, and called for a comprehensive strengthening of AI security.

Despite such concern about the risks around AI, Jim Reid, of Deutsche Bank, said intense competition in the sector meant it was unlikely AI companies would stop investing so heavily in their technology.

“The competitive race between companies and countries remains intense, and it’s difficult to imagine firms voluntarily stepping back while rivals continue to push ahead.” he said. “It is hard to see China standing still.

“If leading executives are openly discussing the risks of increasingly powerful systems, it could be them trying to get across how transformative they believe the technology may become and help advertise the power of their product.

“Rather than signalling less spending, it could simply be that a greater share of AI investment is directed towards safety, monitoring and governance alongside the continued build-out of compute infrastructure.”

Amodei’s warning came before reports emerged that Anthropic is on track to be profitable this quarter.

The company told investors that its adjusted operating income would be positive for a second quarter in a row, according to the Financial Times, in a big milestone as it prepares to list on the US stock market this year.