Stock Market Midday, Sept. 14: Tech Stocks Slide on Dire AI Warnings, Micron Drops 5%

Tech stocks sold off midday September 14, 2026, after AI industry executives called for slower development. Anthropic CEO Dario Amodei and OpenAI CEO Sam Altman issued warnings about risks tied to rapid AI growth, triggering broad declines across the sector.

MU dropped 5% on the AI concerns. CRWD surged 15% as cybersecurity stocks rallied amid the risk-off tone in AI names. META climbed after Goldman Sachs maintained a Buy rating tied to its Muse AI agent. The Nasdaq and S&P 500 each fell 0.44%, while the Dow declined 0.36%.

The split reaction highlights a defensive rotation within tech: investors dumped chip and AI infrastructure plays while bidding up cybersecurity exposure. Goldman's endorsement of META's Muse product suggests the firm sees differentiated AI positioning relative to peers facing regulatory and execution scrutiny.

The executive warnings from two leading AI labs mark a shift in public messaging and injected uncertainty into valuations premised on uninterrupted AI spending growth.