US Stock Indices Fall, AI Stocks Plunge, and Apple Hits $5 Trillion
US major stock indices declined on October 14, with the Nasdaq falling 1.3% and the Philadelphia Semiconductor Index plunging 4.3% to mark its longest losing streak since May 2025. Meanwhile, AI tech stocks experienced severe losses, yet Apple's market capitalization crossed the $5 trillion threshold for the first time. This widespread downturn highlights growing volatility and investor anxiety within the high-flying artificial intelligence sector. However, the divergence shown by tech giants like Apple demonstrates that market capital is shifting toward stable mega-cap companies amid sector-wide corrections. CoreWeave plummeted roughly 15% and Dell dropped 10%, while Asian markets were also hit hard, causing South Korea's Kospi index to briefly trigger a circuit breaker after a drop exceeding 7%.
## BACKGROUND
A circuit breaker is a regulatory financial mechanism that temporarily halts trading on an exchange to curb panic selling and stabilize markets during extreme volatility. The Philadelphia Semiconductor Index is a key benchmark tracking thirty of the largest semiconductor companies involved in the design, distribution, and sale of semiconductors.