Black Tuesday For South Korea's Stock Market, KOSPI Crashes 10% On Chip Sell-Off

South Korea’s benchmark KOSPI index saw a sharp sell-off on June 23, crashing nearly 10% in a single session. The index ended the day at 8,203.84, tumbling 910.71 points or 9.99% from the previous close, marking one of its steepest falls in history.

The decline started right from the opening bell, with the index slipping and struggling to hold the 9,000 level in early trade. Selling pressure intensified around 9:20 a.m., as broader market sentiment weakened sharply across sectors.

By late morning, panic selling triggered market-wide safeguards. Program-based sell orders were temporarily paused in the KOSDAQ market at 11:37 a.m., followed by a sell-side “sidecar” activation on the KOSPI at 11:40 a.m., which curbs algorithmic trading during extreme volatility.

In the afternoon session, losses deepened further, forcing the Korea Exchange to impose a Level 1 circuit breaker at 2:33 p.m. Trading on the KOSPI was halted for 20 minutes after the index fell more than 8% from the previous close and stayed at that level for a minute. The KOSDAQ index also came under heavy pressure, sliding nearly 8% and slipping below the 900 mark.