[Edaily Reporter Shin Ha-yeon ] As the domestic stock market retreated amid a U.S.-driven tech stock sell-off, circuit breakers were triggered in both the KOSPI and KOSDAQ markets. Following the consecutive activation of sell-side circuit breakers in both markets early in the session, trading across the entire market was temporarily suspended in the afternoon as losses exceeded 8%. Even after trading resumed, both the KOSPI and KOSDAQ continued to plummet by more than 8%.

According to MP Doctor on the 15th, as of 1:08 p.m. today, the KOSPI is trading at 5,520.94, down 487.87 points (8.12%) from the previous trading day. The index opened at 5,673.01, down 5.59% from the previous trading day, and hit an intraday low of 5,520.94. The intraday high was 5,751.45.

The KOSDAQ index was also trading at 756.59 at the same time, down 67.29 points (8.17%) from the previous trading day. After opening at 784.45, it fell as low as 755.33 during the session.

As the sharp decline continued, a Level 1 circuit breaker was triggered in the KOSDAQ market at 12:23 p.m. At that time, the KOSDAQ index had plummeted 66.00 points (8.01%) from the previous trading day’s closing price of 823.88 to 757.88. This marks the fifth time this year that a KOSDAQ circuit breaker has been triggered, and the 15th time since the system was introduced.

Subsequently, at 12:38 p.m., a Level 1 circuit breaker was also triggered on the KOSPI market. At that time, the KOSPI had fallen 480.76 points (8.00%) from the previous trading day’s closing price of 6,008.81 to 5,528.05. This marks the 10th time this year and the 16th time overall that the KOSPI circuit breaker has been triggered.

A Level 1 circuit breaker is triggered when the KOSPI or KOSDAQ index falls by 8% or more from the previous day’s closing price and remains at that level for one minute. Upon activation, trading of stocks listed on the relevant market is suspended for 20 minutes, after which trading resumes following a 10-minute single-price trading session. Trading in related equity derivatives is also suspended.

This marks the first time in about two and a half months—since July 29—that circuit breakers have been triggered simultaneously in both the KOSPI and KOSDAQ markets. At that time as well, circuit breakers were triggered in both markets due to a sharp decline in semiconductor-related stocks.

Earlier in the session, sell-side sidecars were also triggered in succession in both markets. On the KOSPI market, the sell-side sidecar was triggered at 9:07 a.m. when the Mini KOSPI 200 futures fell 5.27% from the reference price. On the KOSDAQ market, the sell-side sidecar was triggered at 9:12 a.m. after the KOSDAQ 150 futures fell 6.25% from the previous day’s close and the KOSDAQ 150 index dropped 6.52%.

In terms of supply and demand, foreign investors are currently net sellers of 2.9072 trillion won on the KOSPI market, putting downward pressure on the index. In contrast, retail investors and institutions are net buyers of 1.2169 trillion won and 1.2703 trillion won, respectively. In program trading, there was a net buying of 720.8 billion won in arbitrage trades and a net selling of 544.3 billion won in non-arbitrage trades, resulting in an overall net buying of 176.5 billion won.

Most of the top market-cap stocks are also falling sharply. SamsungElectronics(005930)is trading at 209,500 won, down 9.70% from the previous trading day, while SK hynix(000660)has plummeted 11.28% to 1,259,000 won. SamsungElectronics(1P)(005935)(-10.02%), SKSQUARE(402340)(-10.56%), LG Energy Solution(373220)(-5.69%), SamsungElectroMechanics(009150)(-16.52%), HyundaiMotor(005380)(-6.22%), KB Financial Group(105560)(-1.88%), and Samsung Life Insurance(032830)(-9.33%) are also all trading lower. In contrast, SAMSUNG BIOLOGICS(207940)is trading at 1,226,000 won, up 3.72%, and is the only stock among the top market-cap companies showing strength.

By sector, the electrical and electronics sector is down by around 11%, and most other sectors—including medical and precision equipment, manufacturing, machinery and equipment, construction, securities, distribution, metals, transportation equipment and parts, finance, insurance, chemicals, IT services, textiles and apparel, paper and wood, electricity and gas, real estate, non-metals, transportation and warehousing, general services, and telecommunications—are experiencing sharp declines.

On the KOSDAQ market, retail investors and foreign investors are net buyers of 7.9 billion won and 17.6 billion won, respectively, while institutions are net sellers of 29.2 billion won. Program trading, combining arbitrage and non-arbitrage trades, shows a net buying position of 93.2 billion won.

The trigger for today’s sharp decline was last night’s U.S. stock market. As the U.S. Consumer Price Index (CPI) for September came in stronger than market expectations, concerns over additional interest rate hikes by the Federal Reserve (Fed) intensified once again, and fears of rising financing costs due to high interest rates spread, particularly among artificial intelligence (AI) infrastructure-related stocks. The Nasdaq Composite Index fell 1.88%, and AI infrastructure-related stocks such as Oracle and CoreWeave plummeted.

In South Korea, the ripple effects of the U.S. tech sector’s weakness appear to be amplifying, particularly among major semiconductor stocks. As foreign investors dumped nearly 3 trillion won worth of shares on the KOSPI, SamsungElectronics and SK hynix saw double-digit percentage declines, and selling pressure spread across the entire semiconductor value chain.

The market remains on high alert regarding the possibility of additional market stabilization measures being triggered, as both major indices have continued to fall by more than 8% even after trading resumed. The second-stage circuit breaker is triggered if the index falls more than 15% from the previous day’s close and remains at a level more than 1% below the first-stage trigger index for one minute. The third stage is triggered if the index falls more than 20% from the previous day’s close and remains at a level more than 1% below the second-stage trigger index, at which point trading for the day is halted.