The KOSPI fell more than 8 percent in early trade on the 9th, dropping below 8,000. A slide in U.S. semiconductor shares and a rise in the won-dollar exchange rate combined to push Samsung Electronics below 300,000 won and SK Hynix below 2,000,000 won at the same time. A circuit breaker was triggered on the KOSPI market shortly after the open, while a sell-sidecar was activated on the KOSDAQ market, in a sign of broad sell-offs across local stocks.

According to the Korea Exchange, the KOSPI was down 683.13 points, or 8.37 percent, at 7,477.46 as of 9:04 a.m. It opened down 112.50 points, or 1.38 percent, at 8,048.09 from the previous session, then quickly extended losses after the open and fell below 8,000.

As the selloff continued, the Korea Exchange triggered a circuit breaker on the main board at 9:03:42 a.m. A KOSPI circuit breaker is triggered when the index falls more than 8 percent from the previous session for more than 1 minute. When the first-stage circuit breaker is triggered, trading on the main board is halted for 20 minutes. The circuit breaker is designed to prevent sharp price swings across the market.

By investor type, foreign selling is dragging the index lower. Foreigners are net sellers of 342.1 billion won on the main board. Institutions and individuals are net buyers of 142.1 billion won and 207.1 billion won, respectively, moving in on bargain hunting.

Top market-cap stocks are also broadly weaker. Samsung Electronics was down 30,500 won, or 9.27 percent, at 298,500 won, falling below 300,000 won. SK Hynix was down 166,000 won, or 8.02 percent, at 1,904,000 won, dropping below 2,000,000 won.

Other major large caps were also falling, including SK Square down 11.53 percent, Hyundai Motor down 10.00 percent, Samsung Electro-Mechanics down 9.16 percent, LG Energy Solution down 3.99 percent, Samsung Life down 14.91 percent, HD Hyundai Heavy Industries down 4.97 percent and Samsung C&T down 12.27 percent.

The KOSDAQ also failed to avoid the sharp fall. At the same time, the KOSDAQ was down 74.10 points, or 7.39 percent, at 928.34 from the previous session. A sell-sidecar was also triggered on the KOSDAQ at about 9:06 a.m.

In the Seoul foreign exchange market, the won-dollar exchange rate stood at 1,552.80 won.

The sharp decline is seen as reflecting the shock from U.S. stocks late last week directly into the domestic market. May nonfarm payrolls announced by the U.S. Labor Department far exceeded market expectations, resurfacing concerns that the Federal Reserve may raise interest rates within the year.

This led to heavy selling centered on tech and semiconductor stocks, with Nvidia down 6.20 percent and Micron down 13.25 percent. The Philadelphia Semiconductor Index also plunged 10.26 percent, directly shaking investment sentiment toward domestic semiconductor stocks.

The market sees foreign futures trading, the exchange rate trend and whether losses in Samsung Electronics and SK Hynix narrow during the session as likely to determine the direction of the index.

Even if trading resumes after the circuit breaker, volatility is likely to remain high, focusing attention on whether additional market stabilization measures are triggered during the session.