Kospi Plunges 10.84% as Samsung and SK Hynix Tumble, Dragging Global Chip Stocks

South Korea's Kospi fell 10.84% to 6,023.66 on July 28, 2026 — its worst day since early March. SK Hynix dropped 14.7% and Samsung 13.4%, triggering two circuit-breaker halts (automatic pauses meant to calm panic selling). The selloff spread to Wall Street: Intel, AMD, and Seagate each fell over 4%. Catalysts included China's mass production of homegrown DUV lithography tools and Nvidia's reported $250bn OpenAI datacentre discussions.