South Korea's KOSPI Crashes 10.8% in a Day, Down 34% from June Peak

The South Korean KOSPI Composite Index plunged 10.8% on July 28, 2026, extending its decline to 34% from its June 22 peak in just 25 trading days. The rout was led by chipmakers SK Hynix and Samsung Electronics, which together account for about half of the index. SK Hynix fell 14.4% on the day and 48% from its June high, while Samsung Electronics dropped 13.6% and 41% from its peak. The crash triggered a sell-side sidecar when the index fell 5%, halting program selling for five minutes, and a first-stage circuit breaker at -8%, halting all trading for 20 minutes, but neither stemmed the decline. The KOSPI had previously surged 300% from April 2025 to June 2026, a rally described as a 'consensual hallucination' that replaced cryptocurrencies as speculative vehicles. The current drop has erased about nine weeks of gains, returning the index to April 15 levels. A 71% decline from the peak would be needed to unwind a full year of gains, comparable to the Nasdaq's 78% crash during the US Dotcom Bust. The selloff also dragged down Japan's Nikkei 225, which fell nearly 4%. In the US, the PHLX Semiconductor Index (SOX) has dropped 21% from its June 21 peak.