AI's biggest believers just called for a slowdown — and chip stocks got smoked
Anthropic's CEO wants the world to pump the brakes on AI. Musk and Altman agree. Wall Street heard 'sell semiconductors.
In a twist nobody saw coming, the people who built the AI boom are now asking everyone to slow it down — and investors are dumping the stocks that powered it.
Over the weekend, Anthropic CEO Dario Amodei called for a deliberate, global slowdown in AI development, citing safety concerns including the risk that AI becomes capable of leading a swarm of agents that could "take over the entire internet" within six to 12 months. Then Elon Musk said he agrees. Then OpenAI's Sam Altman backed the idea too.
Wall Street's response was swift and brutal.
The damage
On Monday, the PHLX Semiconductor Sector index — the "SOX" — lost more than 5% of its value. Nvidia, the poster child of the AI trade, sank 3.9% and was the heaviest weight on the market. The Nasdaq composite tumbled 1.2%, while the S&P 500 fell 0.8% for its fifth loss in six days.
The pain went global. In Tokyo, SoftBank Group — a major OpenAI investor — cratered 10.7%. In South Korea, the Kospi dropped 3.3% on losses in Samsung Electronics and SK Hynix, the memory-chip giants feeding the AI data-center frenzy.
The logic is simple: if the labs slow down model development, demand for the chips that train those models could weaken. After two years of blistering gains, chip stocks were priced for perfection — and perfection just got a question mark.
Trump pushes back
Not everyone is on board with hitting the brakes. President Donald Trump pushed back on the slowdown idea, arguing the U.S. needs to stay ahead of China in the AI race.
In a remarkable moment, Trump actually called Nvidia CEO Jensen Huang in the middle of Huang's appearance at the All-In Summit in Los Angeles. Both men downplayed the slowdown calls. Huang has good reason to stay bullish: he recently reiterated he's "confident" in growing Nvidia's revenue 70% next year.
Don't forget the context
As Barron's noted, the AI headlines may just be the excuse the market was looking for. Stocks were already under pressure from the 10-year Treasury yield flirting with 5% and Brent crude jumping past $108 a barrel on Middle East supply fears. Deutsche Bank's Jim Reid put it bluntly: "September lived up to its reputation" as the worst month for stocks.
There are also company-specific crosscurrents. Altman told Fortune in an interview published Saturday that OpenAI would likely wait until next year for a stock sale on Wall Street — potentially delaying a cash gusher for SoftBank and other early investors. The Wall Street Journal separately reported that OpenAI recently bought a startup developing higher-quality smartphone cameras.
What to watch
Chip stocks bounced modestly on Tuesday as the initial panic faded, with the iShares Semiconductor ETF climbing back about 1%. The real test comes with the Fed's rate decision today and the next round of chipmaker earnings. If the AI labs actually throttle back spending, the semiconductor supercycle could face its first real demand shock.
The bottom line: The AI trade's biggest risk was never competition — it was the builders themselves deciding to slow down. For now, Wall Street is treating that as a threat, not a virtue.
