CNBC reports that chip stocks just had their worst week in over a year, with the VanEck Semiconductor ETF sliding 8.9% — its steepest weekly drop since April 2025. The Philadelphia Semiconductor Index fell nearly 10% and is now down more than 20% from its late-June high, confirming a bear market. Nvidia shed 2.2% on Friday, and Apple overtook it as the most valuable US company. The trigger, per CNBC, is investor unease about whether the roughly $725 billion being poured into AI infrastructure will pay off. Analysts quoted argue fundamentals look intact and see this more as a valuation reset than a collapse in AI demand. Worth watching: whether Big Tech earnings this week calm or deepen the nerves.