South Korea’s KOSPI Sinks 10.84% in Biggest Drop Since 1998, Dragged by Samsung and SK Hynix
South Korea's benchmark KOSPI index tumbled 10.84% on March 4, 2026, its steepest one-day loss since March 4, 1998. Memory chip makers Samsung Electronics and SK Hynix, which account for roughly half the index's market capitalization, dragged the market lower in sympathy with overnight weakness in US technology and semiconductor stocks. The Korea Exchange activated circuit breakers twice for the KOSPI and imposed temporary trading halts on the junior Kosdaq index. The rout led declines among Asian chip shares, underscoring the global nature of the sell-off.
On March 4, 2026, South Korea's KOSPI index closed down 10.84%, its biggest one-day percentage decline since March 4, 1998. South Korean stocks led a decline in Asian chip shares that day, in line with broad losses in US technology and semiconductor stocks. The Korea Exchange triggered circuit breakers twice for the KOSPI to curb volatility and also imposed temporary trading halts on the tech-heavy Kosdaq index.
The main drag came from major memory chip producers Samsung Electronics and SK Hynix, which together account for about half of the KOSPI's total market capitalization.