Seoul: South Korean stocks experienced a significant decline of approximately 8 percent late Monday morning after the Korea Exchange (KRX) resumed transactions. This downturn followed a 20-minute trading suspension attributed to extreme market volatility caused by recent U.S.-Israeli strikes on Iran. The benchmark Korea Composite Stock Price Index (KOSPI) fell by 445.88 points, or 7.98 percent, reaching 5,138.99 as of 11:20 a.m.

According to Yonhap News Agency, the KRX implemented a circuit breaker at 10:31 a.m. when the KOSPI plummeted by 452.8 points, or 8.11 percent, to 5,132.07, leading to a 20-minute trading suspension. Circuit breakers are triggered when the index remains 8 percent below the previous session's level for one minute. This is the second instance in a short span, as the KRX issued a circuit breaker last Wednesday when the main index saw a dramatic 12.06 percent decline, the steepest one-day drop since the aftermath of the September 11, 2001, terrorist attacks in the United States.

Earlier Monday, the main bourse operator introduced a sell-side sidecar, halting sales for five minutes. This measure is activated when the KOSPI 200 Futures index shifts 5 percent or more for at least one minute. Investors are closely monitoring global energy price fluctuations, with the U.S. benchmark West Texas Intermediate (WTI) crude surpassing US$100 per barrel on Sunday (U.S. time).

The market also reacted to weaker-than-expected U.S. jobs data released last week, which showed a reduction of 92,000 nonfarm payrolls in February, falling short of market expectations for a gain of 59,000. In the Seoul market, oil refiners traded with mixed results, as SK Innovation dropped 2.8 percent, while S-Oil gained 3.16 percent.

Samsung Electronics, a leading market cap, saw a decline of 9.94 percent, and SK hynix fell by 10.98 percent. Financial shares also lost value, with KB Financial dipping 5.7 percent and Shinhan Financial decreasing by 4.68 percent. Hanwha Aerospace decreased by 4.86 percent, and Hanwha Ocean lost 3.95 percent.

However, POSCO International, a trading firm, rose by 11.06 percent as investors held positive sentiments regarding the firm's energy business portfolio. Meanwhile, the Korean won was trading at 1,497.3 won against the U.S. dollar, marking a decrease of 20.9 won from the previous session.