# KOSPIPlunges9%

South Korea's KOSPI index plunged 9% on July 28, breaking below 6,200 for the first time since April. The Korea Exchange triggered both the sell-side sidecar and circuit breaker mechanisms, halting program sell orders for 20 minutes. Chip stocks bore the brunt. SK Hynix tumbled over 12%, Samsung Electronics dropped more than 10%. The selloff followed a brutal session for U.S. semiconductors — the Philadelphia Semiconductor Index fell over 2%, with SanDisk down 11% and Nvidia off 5%. The trigger: CXMT's debut in China spooked markets over potential disruption to the memory chip oligopoly. Concerns over AI investment returns, peaking memory prices, and fresh supply from CXMT converged in a single session.