European stocks closed sharply lower on Monday as another rise in sovereign yields coincided with concerns that AI safety risks could reduce investment in hardware. The Euro STOXX 50 fell 1.1% to 6,257, while the STOXX Europe 600 dropped 0.5% to 636. Anthropic CEO Dario Amodei urged a slowdown in frontier AI model development, warning that a loss of control over AI agents could harm society; OpenAI and xAI endorsed the call. The prospect of additional guardrails (rules intended to limit AI risks) pressured chipmakers and other AI infrastructure companies, with ASML, Infineon, Schneider Electric and Siemens Energy falling sharply. Banks also declined as renewed Middle East escalation pushed oil and gas prices higher and worsened the eurozone inflation outlook.