AI-linked stocks plunge as industry leaders warn of risks from unchecked development

Dario Amodei, the CEO of Anthropic, published an essay on September 14 warning that AI agents could become capable of seizing control of the entire internet within 6 to 12 months. The response from Wall Street was about as measured as you’d expect: a broad, global sell-off that wiped billions in market value from the companies building the very technology Amodei was describing.

What made the moment genuinely unusual wasn’t one executive sounding the alarm. It was the chorus. Sam Altman of OpenAI and Elon Musk of xAI both echoed Amodei’s concerns, creating a rare alignment among rivals who typically agree on almost nothing.

The damage across markets

Nvidia, the chipmaker that has essentially become the index fund for AI optimism, fell roughly 3% to 3.6%. AMD took a harder hit, dropping as much as 5.7%.

The Philadelphia semiconductor index, a benchmark that tracks chipmakers broadly, shed around 5.1% to 5.5% in early trading.

SoftBank, which has staked enormous sums on OpenAI and other AI ventures, saw its Tokyo-listed shares crater by up to 13%.

The Nasdaq Composite declined between 0.8% and 1.3%.

Amodei’s warning and the IPO that isn’t happening

Amodei’s essay didn’t mince words. He argued that frontier AI models are approaching capabilities that could enable cyberattacks and bioterrorism at scales capable of incurring billions of dollars in damage. His central recommendation: AI companies should voluntarily slow the pace of their most advanced model development.

The sell-off intensified after Altman confirmed that OpenAI would not pursue an IPO this year, citing safety concerns as the primary reason.

A pattern building over months

The September 14 sell-off didn’t emerge from a vacuum. Over the preceding months, a steady trickle of safety researchers had departed prominent AI labs, sometimes with public criticism of their former employers’ approach to risk management.

What this means for investors

Semiconductor stocks are particularly exposed. The 5%-plus drop in the SOX index reflects the market’s recognition that chip demand is a derivative of AI deployment speed.

SoftBank’s 13% plunge is a separate but related story. The company’s strategy under Masayoshi Son has been to concentrate bets on AI’s biggest players.

The shelving of OpenAI’s IPO introduces a liquidity question for private AI companies more broadly. Venture-backed startups that were pointing to an OpenAI public listing as evidence of an eventual exit path now have one fewer data point to show their own investors.

Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.