NVIDIA is trading at $214.24, down 3.48%, as semiconductor shares slide amid concerns about returns on heavy AI infrastructure spending. - Cautious Lam Research guidance is weighing on the sector; a report said NVIDIA was under pressure Thursday as AI-spending sustainability concerns mount. - Major indexes are lower and oil is rising amid Middle East tensions, adding to risk-off pressure. - No clear NVIDIA-specific catalyst was found; Supermicro Vera Rubin news is not evidence of a cause.