[Edaily Reporter Kim Hyung-il ] The KOSPI market extended its upward trend for the second consecutive day as a buy-side circuit breaker was triggered. Following three consecutive trading days of buy-side circuit breakers on the KOSDAQ market through the previous day, the KOSPI also triggered a buy-side circuit breaker today, spreading investor sentiment toward large-cap stocks. This is interpreted as the result of a combination of strong earnings from U.S. artificial intelligence (AI) semiconductor company AMD, a recovery in AI investment sentiment, and buying pressure from foreign investors.

According to MP Doctor on the 5th, the KOSPI closed at 6,598.26, up 239.31 points (3.76%) from the previous trading day. The KOSDAQ also closed at 799.59, up 18.87 points (2.42%). The KOSPI briefly recovered the 6,600 level during the session, and at 9:24 a.m., the buy-side circuit breaker was triggered when the price of the Mini KOSPI 200 futures remained more than 5% above the reference price for over one minute.

The rally in the stock market began in the U.S. As expectations grew for progress in negotiations between the U.S. and Iran over the Strait of Hormuz, international oil prices and market interest rates stabilized, and concerns about the profitability of AI investments eased. AMD reported second-quarter revenue and earnings per share (EPS) that both exceeded market expectations, and its third-quarter revenue forecast also surpassed market expectations. As the Philadelphia Semiconductor Index (SOX) surged, investor sentiment toward domestic semiconductor stocks also improved.

Analysts in the securities industry are suggesting that doubts about AI investments, which had persisted over the past month, are gradually dissipating. Kim Dong-won, an analyst at KB Securities, stated in a recent report, “Earnings from North American cloud companies have confirmed that AI demand is stronger than expected,” adding, “We are entering a phase where skepticism about AI demand is turning into confidence.” He also projected, “Since most cloud infrastructure bookings have been finalized through 2028, the semiconductor market is expected to continue improving alongside expanded AI investment.”

Foreign investors have also begun actively buying stocks, particularly in the semiconductor sector. On that day, foreign investors made net purchases of 1.4464 trillion won on the KOSPI market, driving the index higher. In contrast, retail investors and institutions made net sales of 1.1853 trillion won and 280.2 billion won, respectively. In the KOSDAQ market, retail investors made net purchases of 395 billion won, while foreign and institutional investors made net sales of 298 billion won and 110.8 billion won, respectively.

By sector, construction (6.16%), machinery and equipment (5.58%), and electrical and electronics (4.47%) led the gains. Among the top market-cap stocks, SamsungElectronics(005930)(2.5%), SK hynix(000660)(5.77%), and SamsungElectroMechanics(009150)(14.43%) showed strong performance, and buying momentum spread to AI infrastructure-related sectors such as construction and machinery and equipment. In the KOSPI market, 675 stocks rose, and in the KOSDAQ market, 1,346 stocks—including 11 that hit their daily upper price limit—also rose, as risk-on sentiment spread across the market.

However, gains were partially given back toward the end of the session. This is believed to be due to short-term profit-taking as AMD traded lower in after-hours trading despite reporting strong earnings. Lim Jeong-eun, an analyst at KB Securities, said, “Buying momentum flowed into large-cap stocks, particularly semiconductors, and rotational buying extended to non-semiconductor sectors such as construction, retail, and shipbuilding.” She added, “Given that AMD traded lower in after-hours trading despite reporting earnings that exceeded market expectations, future gains in semiconductor stocks will likely hinge on upcoming earnings announcements.”