South Korea's KOSPI index doubled in 2026, driven by retail investors betting on Samsung and SK Hynix. But concentration risk and AI chip demand concerns

South Korea's KOSPI index plunged 8.3% as Samsung and SK Hynix led a semiconductor sell-off, triggering circuit breakers for the third time in 2026.

South Korea's KOSPI index plunged nearly 10% as SK Hynix and Samsung sell-off triggers circuit breakers, raising doubts about AI-driven stock valuations.