South Korea's stock market took a sharp dive on Tuesday, falling nearly 11% and marking its biggest single-day drop in about five months. A global sell-off in chip stocks hit heavyweights SK Hynix and Samsung Electronics hard.

The benchmark Korea Composite Stock Price Index (KOSPI) closed down 732.09 points, or 10.84%, at 6,023.66, its steepest daily decline since March 4. That date saw a record drop triggered by the outbreak of war with Iran. During the session, the index fell as much as 11.3%, triggering the year's eighth circuit breaker and the 14th in history. It also fell below the 6,000-point threshold for the first time since April 14.

For the month, the KOSPI has dropped 29%, exceeding the previous record monthly loss of 27% set in October 1997. The index is down 34% from its June peak of 9,114.55, but it still holds a 43% gain for the year.

Memory chip maker SK Hynix saw its shares plummet 14.7% after its American Depositary Receipts (ADRs) in New York hit a record low and fell below its US IPO price. Another major component, Samsung Electronics, dropped 14.4%, its biggest single-day loss since October 2008. Together, these two chipmakers account for more than half of the weight in the KOSPI, amplifying the impact of the broader chip sector sell-off on the main index. Both SK Hynix and Samsung Electronics are scheduled to report their second-quarter earnings later this week.

The market turmoil followed a strong debut for China's CXMT (ChangXin Memory Technologies). "The market's focus is not on CXMT's current earnings, but on its potential to accelerate capacity expansion after its IPO, compete with Korean companies, and advance its technological development," said Kim Seok-hwan, a market analyst at Mirae Asset Securities in Seoul.

Other notable decliners included battery maker LG Energy Solution, which fell 5.71%. LG Chem dropped 7.50%, major portal Naver lost 6.67%, and mobile messaging app operator Kakao declined 3.78%. Hyundai Motor fell 9.68%, Kia dropped 6.60%, and steelmaker POSCO Holdings slid 5.38%. In contrast, pharmaceutical company Samsung Biologics edged up 0.26%.

Foreign investors were net sellers of 49,592.21 billion won on the KOSPI. The index is up about 42.72% for the year but has declined 16.8% over the past 30 trading sessions.