AI Safety Warnings From Amodei and Altman Trigger a Global Tech Sell-Off

Technology shares fell sharply around the world on 14 September after two of the artificial-intelligence industry’s most prominent chief executives issued fresh public warnings about the pace and risks of AI development, according to a report from RTÉ.

Anthropic’s chief executive, Dario Amodei, warned that AI agents could become capable of doing hundreds of billions of dollars’ worth of damage — potentially including taking over large parts of the internet — within as little as six to twelve months if development were not slowed. Separately, OpenAI’s Sam Altman said the risks of human extinction posed by advanced AI were unacceptable, and announced that OpenAI would not proceed with a stock market listing this year, citing safety concerns.

Chipmakers Bear the Brunt

The Nasdaq fell as much as 1.7% in early trading. The Philadelphia Semiconductor Index, a closely watched gauge of chip stocks, dropped 6% — its worst day since early July. Nvidia fell 3.5%, Advanced Micro Devices lost 5.6%, and Micron Technology dropped 6.7%.

The sell-off was not confined to the United States. Europe’s technology sector fell 2.3%, with Dutch chip-equipment maker ASML down 6.7% and German industrial groups Infineon and Siemens Energy also posting steep losses. In Asia, Japan’s SoftBank Group — a major AI investor — plunged as much as 13.2%, while South Korea’s KOSPI index, weighed down by chipmakers, tumbled 3.3%, according to a report from UPI.

Software Names Diverge From Hardware

Notably, the reaction was not uniform across the AI trade. While chip and hardware stocks sold off heavily, some software names rallied, suggesting investors were repricing risk around AI’s physical infrastructure build-out specifically, rather than retreating from AI-linked equities as a whole.

“If this does lead to sort of a slowdown and a rethink of AI spending, that will have ramifications for the economy,” said Steve Sosnick, chief strategist at Interactive Brokers.

The warnings also followed the resignation earlier in the month of an Anthropic staffer who cited existential AI risk concerns, adding to a sense that safety debates inside the leading AI labs are increasingly spilling into public view — and, on this occasion, into markets that had spent much of 2026 betting heavily on the AI build-out continuing uninterrupted.