Korean stocks tumbled sharply, dragged down by the fallout from a slump in U.S. semiconductor shares and foreign selling. The KOSPI fell more than 5% after a sell sidecar was triggered during the session, while the KOSDAQ dropped below the 1,000 mark intraday—falling into the 900 range for the first time in about three months—before paring losses to close at the 1,000 level.
The KOSPI ended at 8,160.59, down 478.82 points, or 5.54%, from the previous session, according to the Korea Exchange Monday. The index opened at 8,323.20, down 316.21 points, or 3.66%, before widening its losses. At 9:08:25 a.m., a sell sidecar was triggered following a sharp drop in the KOSPI 200 futures index, suspending the effect of program sell orders for five minutes.
By investor type, selling by foreigners and institutions pulled the index down. On the main bourse, foreigners and institutions net sold 3.5391 trillion won and 939.9 billion won, respectively. Individuals, by contrast, net bought 4.2212 trillion won.
Most top market-cap stocks also declined. Samsung Electronics (005930.KS) closed at 329,000 won, down 6.40%, while SK hynix (000660.KS) ended at 2.07 million won, down 9.92%. Samsung Electronics preferred shares (-4.09%), SK Square (-7.57%), LG Energy Solution (-1.90%), Samsung Life Insurance (-5.82%) and Samsung C&T (-13.93%) all weakened. By contrast, Samsung Electro-Mechanics (2.39%) and HD Hyundai Heavy Industries (2.00%) closed higher. Hyundai Motor was flat at 700,000 won.
The KOSDAQ also weakened. The KOSDAQ index closed at 1,002.44, down 47.29 points, or 4.50%, from the previous session. During trading, it fell as low as 992.80, breaking below the 1,000 mark. It was the first time in two months, since March 4, that the KOSDAQ index traded below 1,000 intraday. The index then pared losses along with the KOSPI, eventually closing in the low 1,000 range.
On the KOSDAQ market, foreigners net sold 182 billion won, leading the index's decline. Individuals and institutions, by contrast, net bought 33.9 billion won and 144.8 billion won, respectively. Among top market-cap stocks, most declined, including Alteogen (-4.04%), Ecopro BM (-8.76%) and Ecopro (-8.00%).
The day's sharp drop is attributed to the direct impact of a correction in U.S. semiconductor shares. Overnight on the New York stock market, Broadcom plunged 12.59% after offering artificial intelligence (AI) revenue guidance that fell short of market expectations. Other chip-related stocks, including Micron (-7.74%) and SanDisk (-3.92%), all weakened.
"Investor sentiment toward the semiconductor sector contracted after Broadcom offered third-quarter AI revenue guidance of $16 billion, below the market estimate of $17.2 billion," said Lee Kyung-min, a researcher at Daishin Securities. "In the domestic market as well, profit-taking emerged centered on the semiconductor sector, leading to a broad decline."
