TLDR
- Nasdaq fell 1.3%, the Dow dropped around 256 points, and the S&P 500 declined 0.8% on Monday
- Anthropic CEO Dario Amodei published a 3,800-word essay calling for a global slowdown in AI development
- OpenAI CEO Sam Altman and Elon Musk backed Amodei’s position
- OpenAI delayed its IPO to 2027 over AI safety concerns; Anthropic still plans to list on the Nasdaq this fall
- Oil prices rose near $108 per barrel after Saudi Arabia shut down a key pipeline, adding more pressure on markets
US tech stocks fell sharply on Monday after the CEOs of the two biggest AI companies called for the industry to slow down the pace of AI development. The move caught Wall Street off guard and sent chip stocks lower.
The Nasdaq Composite dropped 1.3%. The S&P 500 fell 0.8%, and the Dow Jones Industrial Average lost around 256 points, or 0.49%.

Anthropic CEO Dario Amodei published a lengthy essay over the weekend, totaling 3,800 words. In it, he argued that AI companies need to slow how fast they improve their models so the industry can address safety concerns properly.
“We must slow the pace at which we improve the capabilities of AI models,” Amodei wrote. He added that progress would still look fast, and that the time gained should be used wisely.
Sam Altman, CEO of OpenAI, agreed with Amodei in a post on the social media platform X. Elon Musk also voiced support for the position. The alignment between these leaders put them at odds with Wall Street expectations.
I agree with Dario that we need to pace the frontier. This has been a primary topic of discussions we've had at OpenAI in recent weeks.
Committing to having independent evaluators with employee-like access is a great idea, and we will do the same. We'll have more to share soon. https://t.co/1YhhIybZX7
— Sam Altman (@sama) September 12, 2026
AI Safety Concerns Shake Investor Confidence
Markets had been pricing in a steady, fast-moving pace of AI development. The calls for a slowdown raised questions about how quickly AI companies would spend on infrastructure, chips, and data centers.
Chip stocks took some of the hardest hits. Nvidia shares fell as part of the broader tech selloff. In Asia, Samsung dropped over 4%, and SK Hynix also saw losses.
Not all analysts were alarmed. Jeffrey Favuzza, senior vice president at Jefferies, said there was no clear sign that capital spending would actually moderate. He noted that Amodei was not calling for a halt to model training.
Mizuho analyst Jordan Klein told investors not to panic, saying “actions speak louder than words.” He drew a clear line between writing an essay and actually cutting investment.
IPO Plans and Oil Prices Add to Market Pressure
The news also affected IPO timelines. Altman told Fortune that OpenAI is pushing its public offering to 2027 due to AI safety concerns. Anthropic, however, still plans to list this fall and has reportedly chosen the Nasdaq as its exchange.
Oil prices added another layer of pressure on Monday. Brent crude traded near $108 per barrel after Saudi Arabia shut down a key pipeline. The ongoing conflict in the Middle East continued to push energy prices higher.
Traders are now watching the Federal Reserve closely. Rate hike odds jumped to 88% following Friday’s inflation data. Fed Chairman Kevin Warsh has said he will not offer forward guidance ahead of Wednesday’s policy meeting.
Wall Street is selling now and waiting for clarity later.
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