Kospi Suffers ‘Black Tuesday,’ Plunges 9.99% as Record Drop Sends Index to 8,204.06

Kospi triggers fourth circuit breaker of the year

Index loses 910.49 points in biggest one-day drop on record

South Korean stocks tumbled as weakness in global technology shares and a sharp slide in semiconductor stocks hammered sentiment. The Kospi plunged nearly 10%, ending the session back in the 8,200 range, while the Kosdaq dropped almost 8%. A circuit breaker was triggered on the main board for the fourth time this year, underscoring a sharp deterioration in investor sentiment.

According to the Korea Exchange, the Kospi closed at 8,204.06 on June 23, down 910.49 points, or 9.99%, from the previous session. The 910.49-point loss was the largest on record. The benchmark fell more than 8% during the session, triggering a circuit breaker, and ultimately slid to the 8,200 level.

The Korea Exchange halted trading on the benchmark stock market for 20 minutes from 2:33:43 p.m. on June 23. The suspension was triggered after the Kospi stayed down more than 8% from the previous close for one minute, meeting the threshold for a circuit breaker. It was the fourth Kospi circuit breaker this year and the 10th on record.

Earlier, at 11:40:44 a.m., a sell-side sidecar was activated after the Kospi 200 futures index fell more than 5%. The Kosdaq market also triggered a sell-side sidecar at 9:06:02 a.m. It was the first time in 15 days, since June 8, that sell-side sidecars were activated simultaneously on the main board and the Kosdaq market.

The slump appeared to reflect weakness in US technology shares and broader global risk aversion spilling into South Korea’s stock market. Overnight, the Nasdaq Composite fell 1.32% and the S&P 500 dropped 0.37%. Investor sentiment weakened as profit-taking hit artificial intelligence-related stocks and concerns grew over an outflow of AI talent.

On the main board, retail investors were net buyers of 11.1116 trillion won. Foreign investors were net sellers of 5.7917 trillion won, while institutions sold a net 5.4865 trillion won.

Most of the biggest stocks by market value posted losses close to double digits. SK Hynix, which became the market’s most valuable company a day earlier, fell 12.47% to 2.555 million won, while Samsung Electronics dropped 12.31% to 310,000 won. Samsung Electro-Mechanics lost 10.68%, Samsung C&T sank 12.50%, Hyundai Motor slid 12.05%, Kia fell 9.25% and HD Hyundai Heavy Industries dropped 7.55%.

SK Hynix still held the top spot by market capitalization. Its market value stood at about 1,820 trillion won, above Samsung Electronics at about 1,812 trillion won. The gap between the two was about 8.6 trillion won, equivalent to just 0.5%.

The Kosdaq closed at 891.55 on June 23, down 76.85 points, or 7.94%, from the previous session.

On the Kosdaq, foreign investors were net buyers of 310.2 billion won and institutions bought a net 135.6 billion won. Retail investors were net sellers of 463.7 billion won.

In Seoul trading, the won-dollar exchange rate closed at 1,539.1 won per dollar, up 2.1 won from the previous session.

Kim Yeon-ji, Hankyung.com reporter kongzi@hankyung.com