South Korea’s KOSPI plunges over 8 percent at the open, circuit breaker freezes trading
South Korea’s main stock index dropped more than 8 percent within minutes of Friday’s open, falling below the 5,000 mark for the first time in nine months and triggering a 20-minute trading halt.
The Korea Exchange activated its Level 1 circuit breaker at 9:03 a.m. local time after the KOSPI stayed down at least 8 percent from the prior close. The index opened near 5,263 and quickly sank to around 4,923–4,924, a loss of roughly 8.5 percent from Thursday’s close of 5,383.80. Trading resumed after the pause, but selling pressure remained heavy.
The move extends a sharp multi-day decline driven by a global sell-off in technology and semiconductor stocks. Investors reacted to Democratic Party gains in the U.S. midterm elections, which raised concerns that tighter rules on AI data centers could slow spending and delay projects. U.S. markets had already posted their worst session in more than a year on Thursday, with heavy losses in chip names.
Samsung Electronics and SK Hynix, which together make up nearly half of the KOSPI’s market capitalization, led the drop. Samsung fell about 10 percent and SK Hynix dropped 11–13 percent in early trade. The broader market’s heavy reliance on these two memory-chip makers left the index exposed to any shift in AI hardware demand.
The KOSPI is now down roughly 46 percent from its record high earlier in 2026, when it climbed above 9,000 on the strength of the AI boom. Friday’s halt was the 11th circuit-breaker activation on the main board this year. Foreign investors have been net sellers during the recent weakness, while the tech-heavy KOSDAQ also faced temporary restrictions on program trading.
The sell-off reflects the market’s concentration risk and the sensitivity of Korean chip exporters to U.S. policy and global technology spending. Authorities said they are monitoring conditions, but the immediate reaction has been driven by valuation concerns after a rapid prior advance.