Securities

Samsung Plummets 7%, SK Hynix Falls 9%... KOSPI Triggers Sell-Side Circuit Breaker Immediately After Opening

KOSPI Down 6.61%… Foreign and Institutional Investors Jointly Sell Off 1.5 Trillion Won Investor Sentiment in Semiconductors Plummets Amid Surging U.S. Long-Term Interest Rates and Oil Price Volatility SKSQUARE Down 11%, SamsungElectroMechanics Down 4%… Blue-Chip-Related Stocks Also Weak KOSDAQ Also Falls Over 3%… Foreign Investors Are the Only Net Buyers

KIM YOON-JEONG
2026-08-19 09:01:28
[Edaily Reporter KIM YOON-JEONG ] The KOSPI plunged more than 6% in early trading on the 19th, falling to the 6,400 level. Amid a sharp rise in U.S. long-term Treasury yields and oil price volatility stemming from the Middle East, U.S. semiconductor stocks fell sharply overnight, triggering a wave of selling in domestic semiconductor stocks as well. Following sharp declines of around 7% and 9% for SamsungElectronics and SK hynix, respectively, SKSQUARE is down more than 11%, and SamsungElectroMechanics is down around 4%.
Major indices are displayed on an electronic board in the Hana Bank trading room in Jung-gu, Seoul, on the morning of the 19th. The KOSPI opened at 6,528.77, down 4.96% from the previous trading day. The KOSDAQ index opened at 810.08, down 2.89% from the previous trading day. The won-dollar exchange rate is trading at 1,413.5 won.(Photo = Newsis)

According to MP Doctor, as of 9:19 a.m. today, the KOSPI stood at 6,415.96, down 453.87 points (6.61%) from the previous trading day. The index opened at 6,528.77, down 341.06 points (4.96%) from the previous close, and extended its losses during the session, falling as low as 6,403.31.
In terms of supply and demand, based on data aggregated by Nextrade (NXT), retail investors are net buyers of 1.5395 trillion won worth of stocks on the stock market. In contrast, foreign investors and institutions are net sellers of 1.00807 trillion won and 428.6 billion won, respectively.
At 9:06 a.m., shortly after the market opened, the KOSPI 200 futures price fell 6.02% from the reference price, triggering the sell-side circuit breaker on the stock market. As a result, the execution of program sell orders was temporarily suspended for five minutes.
Overnight, U.S. stock markets fell across the board as rising long-term Treasury yields coincided with oil price volatility stemming from the Middle East. The Nasdaq fell 1.33%, and the S&P 500 fell 0.69%. Investor sentiment was weighed down by rising international oil prices—driven by fading hopes for U.S.-Iran negotiations—and the yield on the 30-year U.S. Treasury note, which rose to 5.337% during the session, its highest level since 2007.
In particular, selling pressure centered on artificial intelligence (AI) and semiconductor stocks due to concerns over rising interest rates. The Philadelphia Semiconductor Index (SOX) plummeted 4.98%, with Micron (-7.06%), SanDisk (-8.89%), and Western Digital (-7.43%) all posting sharp declines. SK hynix American Depositary Receipts (ADRs) also plunged 9.20%.
Han Ji-young, an analyst at KIWOOM Securities, said, “The domestic stock market is expected to open lower today due to rising long-term interest rates in major economies, weakness in U.S. semiconductor stocks, and the aftermath of the KOSPI 200 overnight futures plunging by over 4%.” She added, “However, since the pressure for a market correction driven by interest rates was largely priced in following yesterday’s sharp decline, I believe the market will recover some of its losses during the trading session.”
SamsungElectronics(005930), the company with the largest market capitalization on the KOSPI, is trading at 249,000 won, down 19,500 won (7.26%) from the previous trading day. SK hynix(000660), the second-largest by market capitalization, is extending its losses, trading at 1,509,000 won after plummeting 153,000 won (9.21%).
Selling pressure is also spreading to stocks related to the market leaders. SKSQUARE(402340)is trading at 1,003,000 won, down 132,000 won (11.63%) from the previous trading day. SamsungElectroMechanics(009150)is also down 61,000 won (4.24%) to 1,379,000 won. SamsungElectronics(1P)(005935) is likewise down 7.75%.
In addition, HyundaiMotor(005380)(-6.21%), LG Energy Solution(373220)(-2.14%), SAMSUNG BIOLOGICS(207940)(-2.42%), KB Financial Group(105560)(-4.81%), and Samsung Life Insurance(032830)(-10.63%) are all down. On the other hand, HANWHA AEROSPACE(012450)(4.01%) is on the rise.
The KOSDAQ is also down by more than 3%. As of this writing, the KOSDAQ index stands at 808.75, down 25.45 points (3.05%) from the previous trading day.
In the KOSDAQ market, foreign investors are net buying 55 billion won worth of stocks. In contrast, retail investors and institutional investors are net selling 8.8 billion won and 42.7 billion won worth of stocks, respectively.
Among the top-market-cap stocks on the KOSDAQ, Alteogen Inc.(196170)is trading at 292,000 won (-2.01%), ECOPRO CO., LTD(086520)at 84,700 won (-2.76%), and ECOPRO BM CO., LTD.(247540)at 106,200 won (-2.66%).
In addition, Rainbow Robotics(277810)(-3.09%), JUSUNG ENGINEERING Co.,Ltd.(036930)(-4.13%), HLB INC.(028300)(-3.94%), WONIK IPS Co.,Ltd.(240810)(-3.65%), LEENO Industrial Inc(058470)(-5.31%), ABL Bio Inc.(298380)(-2.13%), and SAM CHUN DANG PHARM CO. LTD(000250)(-4.22%) are all trading lower. On the other hand, EO Technics Co., Ltd.(039030)(1.09%) is trading higher.

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