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.

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 Korean stocks plunged sharply on Tuesday, with the Kospi falling over 8% from record highs as investors sold off major chip stocks amid concerns that the market rally had…