The Nasdaq 100 and chipmaker stocks fell after Anthropic CEO Dario Amodei called for a slowdown in AI development, a stance Sam Altman and Elon Musk have echoed. Bloomberg says the S&P 500's roughly $33 trillion in gains since ChatGPT's late-2022 launch now hinges on that same AI trade continuing.
The Nasdaq 100 and chipmaker stocks declined as markets reassessed the pace of AI infrastructure investment, after Amodei's September 14 call for slower AI development, citing safety risks — a position Sam Altman has also echoed publicly, alongside past comments from Elon Musk. Nvidia fell 3.4% that day, and SoftBank dropped 10.7%.
Bloomberg flags $33 trillion at risk
The S&P 500 has added roughly $33 trillion in market value since ChatGPT launched in late 2022, Bloomberg noted. Bloomberg Economics estimates AI-related investment contributed to roughly half of US GDP growth over the past year, with the economy expanding around 2%.
A concentrated bet
US venture funding topped $400 billion in the first half of 2026, with AI startups capturing most of it. Investor flows into IT-focused ETFs have surged to $52 billion since late March 2026, against a comparatively modest $4 billion for the rest of the market — a 13-to-1 ratio in favor of tech.
Prediction markets reprice Anthropic
Prediction markets moved too. The odds of Anthropic's valuation reaching $600 billion by December 31, 2026 fell to 1.8% for a YES outcome, a pricing shift that reflects a broader reassessment of the growth assumptions that had been driving AI-linked investments.
Sources: Crypto Briefing, Crypto Briefing
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