South Korea’s KOSPI index fell 9.99% on June 8, 2026, its worst single-day performance since a 12.06% collapse on March 4 of the same year.
The trigger was stronger-than-expected US jobs data, which investors read as a green light for the Federal Reserve to keep interest rates elevated longer than markets had priced in. Higher rates mean tighter financial conditions globally, and when Wall Street tech stocks sold off on that fear, Asian markets caught the contagion fast.
What actually happened
The index briefly declined around 8.3% before closing near the 10% mark, triggering circuit breakers during the session.
Samsung Electronics and SK Hynix, two of the KOSPI’s heaviest-weighted components, posted outsized losses on the day. Both companies are deeply embedded in the global AI and semiconductor supply chain, which makes them particularly sensitive to any repricing of tech-sector growth expectations.
