On the 11th, the domestic stock market, which opened higher on the U.S. interest rate cut decision, ultimately closed lower. Volatility widened on "quadruple witching," the expiration day for four derivatives—index futures and options and single-stock futures and options—preventing the market from recovering losses into the close. The U.S. company Oracle also released results that were weaker than expected, delivering a significant shock to the market.
The KOSPI index finished the session at 4,110.62, down 24.38 points (0.59%) from the previous trading day. The KOSPI opened at 4,163.32, up 28.32 points (0.68%) from the day before, and climbed to 4,170.77 intraday, but turned lower in the afternoon as foreigners shifted to net selling.
The KOSDAQ index moved similarly. The KOSDAQ started at 940.59, up 5.59 points (0.60%) from the previous day, and rose to 943.19 intraday, but failed to find direction and closed at 934.64, down 0.36 points (0.04%) from the day before.
In the main board, individuals and institutions were net buyers of 130 billion won and 120 billion won, respectively, supporting the index. Foreign investors alone were net sellers of 260 billion won. On the KOSDAQ market, individuals and foreigners showed a buying advantage of 75 billion won and 7 billion won, respectively.
Large-cap KOSPI stocks were designated "investment warning issues," weighing on share prices. SK hynix (-3.75%), SK Square (-5.09%) and Hyundai Rotem (-4.17%)—all top market-cap names—were included. When a stock is designated an investment warning issue, margin trading is restricted, and share prices tend to struggle.
Oracle's weak results also affected the market. Overnight, Oracle released quarterly revenue and operating profit that missed estimates and raised its capital expenditure outlook, sending the stock down more than 11% in after-hours trading. As worries resurfaced about artificial intelligence (AI) profitability, Samsung Electronics (-0.65%) and HANMI Semiconductor (-0.08%) were weak.
The stronger Japanese yen also weighed on stocks. With the Federal Reserve's rate cut overnight and the Bank of Japan (BOJ) expected to raise rates on the 19th, concerns about the unwinding of yen carry trades resurfaced. The dollar-yen rate, which approached 157 yen the previous day, reversed lower and fell to as low as 155.5 yen intraday.
Lee Kyung-min, a researcher at Daishin Securities Co., said, "Recent psychological jitters, such as earthquake alerts in northeastern Japan, also amplified concerns," adding, "However, with yen-strength worries already priced into the market, unless a shocking natural disaster occurs, concerns about the stronger yen will gradually ease."
Among the top market-cap names on the main board, performances were mixed. LG Energy Solution (1.02%), Doosan Enerbility (0.65%) and Samsung Biologics (0.24%) rose. In contrast, Hyundai Motor (-2.31%) and HD Hyundai Heavy Industries (-2.1%) closed at lower prices than the previous day.
All of the top 10 KOSDAQ market-cap stocks fell. Alteogen (-0.66%), EcoPro BM (-3.18%), ABL Bio (-3.3%) and Kolon TissueGene (-1.33%) were among them.