[Edaily Reporter Kim Hyung-il ] The domestic stock market closed lower across the board, weighed down by selling pressure that persisted from the opening bell. Although artificial intelligence (AI)-related stocks performed strongly on U.S. markets overnight, uncertainty surrounding NVIDIA and supply-demand volatility due to options expiration dampened investor sentiment. The index, which had surged sharply over the past two days, gave up some of its gains, and the KOSDAQ index fell below the 700-point mark.

According to MP Doctor on the 12th, the KOSPI closed at 5,342.73, down 32.63 points (0.61%) from the previous trading day. The KOSDAQ closed at 696.53, down 8.57 points (1.22%).

The KOSPI opened at 5,385.94, up 10.58 points (0.20%) from the previous trading day, but turned lower early in the session. As selling pressure intensified in the afternoon, the index slipped to the 5,350 level during the session and ultimately closed in the 5,340 range. The KOSDAQ also failed to recover the 700-point mark, posting a decline of over 1%.

In both markets, the number of stocks that fell exceeded those that rose. On the KOSPI, 271 stocks rose, 45 remained unchanged, and 595 fell. On the KOSDAQ, 571 stocks rose, 85 remained unchanged, and 1,097 fell.

On the KOSPI, mid- and small-cap stocks saw larger declines than large-cap stocks. While the large-cap index fell 0.57%, mid-cap and small-cap stocks dropped 1.01% and 1%, respectively. By sector, IT services posted the largest decline, falling 3.11%. Insurance and chemicals also showed weakness, falling 2.28% and 1.89%, respectively.

Among the top market-cap stocks, SamsungElectronics(005930)closed at 208,000 won, up 0.97% from the previous trading day. SamsungElectronics(1P)(005935)also rose 2% to close at 168,300 won, while SAMSUNG BIOLOGICS(207940)and Samsung Life Insurance(032830)rose 1.33% and 1.01%, respectively. In contrast, SK hynix(000660)closed at 1,254,000 won, down 1.8%, and SamsungElectroMechanics(009150)fell 4.01%. HyundaiMotor(005380)and LG Energy Solution(373220)also fell 2.20% and 1.79%, respectively.

On the KOSDAQ, the metals sector fell 2.58%, while general services and pharmaceuticals also declined by 2.23% and 2.08%, respectively. Among the top market-cap stocks, JUSUNG ENGINEERING Co.,Ltd.(036930)fell 3.59%, and Alteogen Inc.(196170)also dropped 3.32%. ECOPRO BM CO., LTD.(247540)and SAM CHUN DANG PHARM CO. LTD(000250)also fell by 2.18% and 2.15%, respectively. In contrast, SIMMTECH Co., Ltd.(222800)rose 1.89%, and LEENO Industrial Inc(058470)also gained 0.96%.

In terms of supply and demand, the KOSPI and KOSDAQ markets showed divergent trends. On the KOSPI, foreign investors were net buyers of 150.7 billion won, while institutional investors were net sellers of 774.6 billion won. Retail investors also showed a net buying position of 78.5 billion won. On the KOSDAQ, foreign investors were net sellers of 427.2 billion won, while retail and institutional investors were net buyers of 303.3 billion won and 38.3 billion won, respectively.

Overnight, U.S. stock markets closed higher, buoyed by strength in AI-related stocks. CoreWeave’s announcement of strong third-quarter results and an upward revision to its full-year outlook eased concerns over AI infrastructure demand and funding, while news of Anthropic’s successful initial public offering (IPO) also bolstered investor sentiment. The Philadelphia Semiconductor Index surged by over 5%, and the three major U.S. stock indices—which had fallen the previous day due to concerns over the U.S. Consumer Price Index (CPI)—all rose.

However, the mood shifted after the market closed as controversy surrounding NVIDIA surfaced. Following reports of allegations that CEO Jensen Huang had an extramarital affair with a female executive and that the board was considering his dismissal, NVIDIA’s stock price plummeted by over 8% in after-hours trading. As uncertainty surrounding AI investment sentiment grew, the momentum for a rebound in the domestic stock market was limited.

Lim Jeong-eun, an analyst at KB Securities, analyzed, “The domestic stock market is showing signs of a partial pullback from recent sharp gains, as investor sentiment has been dampened by uncertainty stemming from NVIDIA, compounded by supply-and-demand volatility on options expiration day.” Regarding foreign investor flows, she noted, “While net buying on the KOSPI has continued for three consecutive trading days, it remains limited compared to the cumulative net selling volume in November.”

Researcher Lim continued, “Foreign investors have made net purchases of 1.7 trillion won on the KOSPI over the past three trading days,” adding, “Considering that net sales in November totaled 10 trillion won, this is a limited amount.” He also noted, “We need to pay close attention to how AI investment sentiment shifts following Nevius’s earnings announcement this evening.”