As the domestic stock market opened lower due to the ripple effects of weakness in U.S. tech stocks, the KOSPI plunged more than 5%, triggering a sell-side circuit breaker.

As of 10:18 a.m. on the 6th, the KOSPI index stood at 6,249.5, down 5.29% (348.76 points) from the previous trading day. The KOSPI opened the session with a 1.81% decline before the drop widened rapidly. At the same time, the KOSDAQ index also fell 2.53% (20.21 points) to settle at 779.38.

As the KOSPI showed a sharp decline in the 4–5% range, the Korea Exchange implemented a temporary suspension of program sell orders (sell-side circuit breaker) on the securities market at 10:18:12 a.m. This was triggered when the KOSPI 200 futures index recorded 987.24, down 5.04% from the previous closing price.

A sell-side circuit breaker is activated when the KOSPI 200 futures index remains down 5% or more from the base price for one minute, subsequently suspending the effectiveness of program sell orders for five minutes to prevent a flood of sell volumes from hitting the market all at once.

In the market, major stocks, centered around large-cap artificial intelligence (AI)-related shares, suffered steep losses. As of 10:21 a.m., Samsung Electronics was trading down 6.30% at 230,500 won, while SK Hynix fell 9.47% to 1.51 million won. SK Square (-10.90%) and Samsung Electro-Mechanics (-10.30%) also posted steep declines.

Meanwhile, a total of 46 circuit breakers have been triggered in the securities market so far this year, of which 24 were sell-side circuit breakers and 22 were buy-side circuit breakers.