The KOSPI rebounded on the 16th after seven straight sessions of losses, while the KOSDAQ climbed steeply enough to trigger a buy-side sidecar during the session. Most large-cap stocks advanced, with the sharpest gains in shares less closely tied to artificial intelligence, a sector drawing growing caution.
The KOSPI closed at 5,668.05, up 113.83 points, or 2.05%, from the previous session, according to the Korea Exchange (KRX). The index opened at 5,653.99, up 99.77 points or 1.80%, and at one point rose 2.60% to 5,809.94. The KOSDAQ ended at 794.78, surging 33.96 points, or 4.46%. It opened at 772.17, up 11.35 points or 1.49%, and briefly reclaimed the 800 level at 807.54, a gain of 6.14%. The steep advance prompted the KRX to trigger a buy-side sidecar on the KOSDAQ market at about 12:55 p.m.
Most of the market's largest stocks finished higher. Samsung Electronics closed at 215,500 won, up 2.62%, while SK hynix ended at 1.272 million won, up 0.79%. In the previous session, when the index plunged, Samsung Electronics fell 9.48% and SK hynix dropped 11.06%.
Gains were most pronounced in sectors with less exposure to the AI industry. Hyundai Motor closed at 312,000 won, up 5.58%, while Samsung Biologics rose 4.09%, Samsung Life Insurance 4.61%, Samsung C&T 7.10%, Hanwha Aerospace 7.77% and Celltrion 6.53%. On the KOSDAQ, biotech firms also surged, with Alteogen up 9.60% and Pharma Research up 7.54%.
Doubts have been mounting in domestic and overseas markets over current valuations of AI companies. In the U.S., shares of CoreWeave, a cloud provider specializing in AI, fell more than 15% after the yield on corporate bonds it issued to expand data centers approached 15%, bringing its heavy borrowing burden into focus. Research firm Gartner projected that cumulative AI infrastructure investment will reach $7 trillion between 2026 and 2030, while data center revenue will total only $3.6 trillion.
Local brokerages, however, are focusing on corporate earnings fundamentals. Earnings forecasts for Samsung Electronics and SK hynix have been revised upward recently. ASML said in its latest earnings release that customers' medium- to long-term demand outlook is improving, and research firm TrendForce projected double-digit percentage gains in DRAM prices in the fourth quarter of this year. Some market participants argue that, given these factors, the recent plunge in shares of Samsung Electronics and SK hynix reflects an excessive pricing-in of risk aversion.
"The recent plunge in the domestic stock market was excessive relative to earnings forecasts for major companies," a securities industry official said. "There is a possibility of a W-shaped rebound, with shares rising after passing a bottom."
