[Edaily Reporter Kim Hyung-il ] The KOSPI closed up more than 3%, buoyed by a recovery in AI investment sentiment driven by the U.S. and expectations of easing tensions in the Middle East. Although the index recovered to the 6,600 level early in the session—triggering a “buy-side sidecar” (a temporary suspension of buy orders in program trading)—it gave up some of its gains in the afternoon. The fact that U.S. AI semiconductor company AMD posted strong earnings but still traded lower in after-hours trading is also seen as weighing on investor sentiment.

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%).

On that day, a buy-side sidecar was triggered in the KOSPI market at 9:24 a.m. This marked the 22nd buy-side sidecar triggered this year; including sell-side sidecars (23 occurrences), it was the 45th overall. The Korea Exchange explained that the trigger conditions were met because the price of the Mini KOSPI 200 futures rose more than 5% above the reference price and remained at that level for over one minute. Following the activation, the effectiveness of buy orders in program trading was suspended for five minutes before automatically resuming. Following the activation of buy-side sidecars for three consecutive trading days on the KOSDAQ market, the activation on the KOSPI market as well signaled that risk appetite was spreading to large-cap stocks.

Overnight, U.S. stock markets rose across the board as expectations for progress in negotiations between the U.S. and Iran over the Strait of Hormuz grew, spreading optimism about an easing of geopolitical tensions in the Middle East, coupled with a recovery in AI investment sentiment. In particular, AMD reaffirmed expectations for expanded investment in AI data centers by reporting second-quarter earnings that exceeded market expectations and presenting a positive third-quarter revenue outlook. Consequently, the Philadelphia Semiconductor Index (SOX) rose sharply, drawing buying interest into domestic semiconductor stocks. However, despite its strong earnings, AMD traded lower in after-hours trading, leading analysts to suggest that the potential for further gains in semiconductor stocks will hinge on the earnings reports of other companies and whether the momentum for AI investment continues.

In terms of supply and demand, foreign investors led the KOSPI’s rise by purchasing 1.4464 trillion won worth of shares. Retail investors and institutions sold 1.1853 trillion won and 280.2 billion won, respectively. On the KOSDAQ, retail investors bought 395 billion won worth of shares, while foreign investors and institutions sold 298 billion won and 110.8 billion won, respectively.

By market capitalization on the KOSPI, large-cap stocks led the rally with a 3.87% gain, while mid-cap (2.76%) and small-cap (1.72%) stocks also rose. By sector, construction (6.16%), machinery and equipment (5.58%), and electrical and electronics (4.47%) posted the largest gains. Cyclical sectors such as transportation equipment and parts (3.45%) also showed strength, supporting the KOSPI’s rise, while the financial sector (3.21%) also performed well. Analysts suggest that the rally, which began in the semiconductor sector, spread to AI infrastructure and cyclical sectors, leading to a rotation of buying across the board.

Among the top KOSPI stocks by market capitalization, SamsungElectronics(005930)(2.5%), SK hynix(000660)(5.77%), SamsungElectroMechanics(009150)(14.43%), HyundaiMotor(005380)(3.06%), and LG Energy Solution(373220)(2.13%) all rose. On the KOSDAQ market, Alteogen Inc.(196170)(3.75%), Rainbow Robotics(277810)(3.64%), JUSUNG ENGINEERING Co.,Ltd.(036930)(5.07%), LEENO Industrial Inc(058470)(3.88%), and HLB INC.(028300)(1.60%) showed strength, while ECOPRO BM CO., LTD.(247540)(-0.78%) posted a decline.

Buying pressure dominated the market overall. On the KOSPI, 675 stocks rose and 197 fell. On the KOSDAQ, 1,346 stocks rose—including 11 that hit their daily upper price limit—while 301 fell.

Kang Jin-hyuk, an analyst at Shinhan Investment Securities, noted, “U.S. semiconductor stocks performed strongly due to stable oil prices and interest rates, as well as easing concerns over AI profitability following Big Tech earnings reports,” adding, “The domestic stock market also saw a stock-picking rally, with buying momentum spreading from semiconductors to non-semiconductor sectors.”

Lim Jeong-eun, an analyst at KB Securities, assessed, “Buying interest flowed into large-cap stocks, particularly in the semiconductor sector, and non-semiconductor sectors such as construction, retail, and shipbuilding rose in tandem,” adding, “Rotational buying continued across all sectors amid improved risk appetite.” She continued, “Given that AMD traded lower in after-hours trading despite reporting earnings that exceeded market expectations, upcoming earnings announcements will serve as a barometer for whether the upward trend in semiconductor stocks will continue.”