The Kospi closing figure is displayed on a screen at the Hana Bank dealing room in Jung-gu, Seoul, on Thursday. [Yonhap]
The Kospi closing figure is displayed on a screen at the Hana Bank dealing room in Jung-gu, Seoul, on Thursday. [Yonhap]

South Korea's stock market extended its extreme volatility through the end of July, buffeted by the Federal Reserve's monetary policy decision, earnings from global big-tech companies, and results from Samsung Electronics and SK Hynix. The Kospi surged more than 5% intraday Thursday, briefly threatening to reclaim the 6,000 level, before surrendering all of its gains and closing down more than 1% at the 5,600 range.

The Kospi finished Thursday down 69.68 points, or 1.23%, at 5,593.56. The index opened up 18.53 points, or 0.33%, at 5,681.77 and climbed as high as 5,976.82 during the session — putting the 6,000 mark within reach — before selling pressure intensified in the afternoon and pushed it into negative territory.

Over the past three trading sessions, the Kospi shed 1,162.19 points, or about 17%. The Kosdaq also swung sharply during the day before closing down 17.90 points, or 2.70%, at 644.78.

Markets absorbed a series of major events that amplified intraday volatility. The Fed's benchmark interest rate decision, big-tech earnings releases, results from Samsung Electronics and SK Hynix, and shifting sentiment around AI semiconductor investment all converged, causing the market to reverse direction multiple times in a single session.

Institutions and foreign investors both moved to buy the dip on the main board Thursday. Foreign investors posted net purchases of 1.3457 trillion won ($928 million) on the Kospi, while institutions added net purchases of 66.3 billion won. Retail investors, by contrast, recorded net selling of 1.43 trillion won in a wave of panic selling that followed the sharp decline.

Among large-cap stocks, semiconductor shares broadly closed lower.

SK Hynix fell 5.64%, Samsung Electro-Mechanics dropped 14.58%, and SK Square declined 6.00%. Samsung Electronics, which posted an earnings surprise, still slipped 0.72%, while Samsung Electronics preferred shares fell 1.56%, Hyundai Motor lost 0.71%, and Samsung Life shed 0.56%. On the upside, LG Energy Solution gained 6.49%, Samsung Biologics rose 3.25%, and KB Financial Group advanced 4.56%.

The frequency and severity of Kospi selloffs this month have reached historically unusual levels. Three sessions in July now rank among the 15 worst single-day declines in the index's history: July 2 (down 7.89%), July 13 (down 8.95%), and July 28 (down 10.84%). The July 28 drop marked the second double-digit percentage decline this year. June had already seen two sharp selloffs — June 8 (down 8.29%) and June 23 (down 9.99%) — but July has surpassed that month in both the number and the magnitude of the drops.


kacew@heraldcorp.com