[Edaily Reporter Kim Hyung-il ] The KOSPI showed a strong upward trend, breaking through the 7,100 mark during the session, but gave up most of its gains as international oil prices surged following news of attacks on Saudi Arabian oil facilities. While foreign and institutional investors continued to buy, primarily in large-cap semiconductor stocks, the index fell sharply toward the end of the session as external uncertainties compounded the situation and rotation trading failed to spread across the broader market.

According to MP Doctor on the 8th, the KOSPI closed at 6,954.52, down 40.87 points (0.58%) from the previous trading day. Although it rose as high as 7,171.52 during the session, breaking through the 7,100 mark, its upward momentum slowed in the afternoon, and it eventually fell below the 7,000 mark. The KOSDAQ also closed down 10.31 points (1.25%) at 811.88.

What shook investor sentiment toward the end of the session was negative news from the Middle East. International oil prices rose by more than 2% following reports of attacks on energy facilities in southern Saudi Arabia, reigniting concerns over supply disruptions in the region. Compounded by trade tensions between the U.S. and Canada and caution ahead of the release of U.S. inflation data, profit-taking selling pressure quickly emerged following the intraday surge. This explains why the KOSPI, which had been extending its gains above the 7,000 mark through the morning, pared its gains in the afternoon before turning lower.

Even the large-cap semiconductor stocks that had driven the rally saw their gains significantly narrow toward the end of the session. SamsungElectronics(005930)rose as high as 276,500 won during the session, up 2.41%, but slipped to 269,500 won, closing down 0.19%. SK hynix(000660) also rose as high as 1,872,000 won during the session, surpassing the 1.8 million won mark, but fell back to 1,793,000 won, ending the day up just 0.56%.

The strength in semiconductor stocks was driven by expectations of increased memory demand stemming from expanded investment in artificial intelligence (AI). Kim Dong-won, an analyst at KB Securities, projected that the high-bandwidth memory (HBM) market would grow by 164% year-over-year in 2027. Analysts predict that SamsungElectronics and SK hynix will benefit as the U.S. and China continue to release new AI models and compete to expand data centers.

Following the semiconductor sector, construction and nuclear power-related stocks also showed strength as expectations for expanded South Korea-U.S. nuclear power cooperation came into focus. Expectations for new orders stemming from cooperation on eight large-scale South Korea-U.S. nuclear power plants and expanded U.S. investment spread to the construction sector. As it was confirmed that nuclear power-related projects would account for 60% of the $200 billion in investment in the U.S., expectations for orders among domestic nuclear power companies also grew.

However, the upward trend did not spread widely across the broader market that day. On the KOSPI, only 231 stocks rose, while 634 fell; on the KOSDAQ, 506 stocks rose, but 1,141 fell. This suggests that the strong buying momentum centered on semiconductors the previous day did not sufficiently spread to other sectors and stocks.

In terms of supply and demand, foreign investors and institutions recorded net purchases of 583.3 billion won and 802.4 billion won, respectively. While the combined net purchases by these two groups totaled 1.3857 trillion won, retail investors recorded net sales of 3.1086 trillion won. Foreign investors and institutions continued to make net purchases on the KOSPI for the fourth consecutive trading day. The continued strength of the won—with the won-dollar exchange rate falling to the 1,330 won range during the session—also acted as a favorable factor for foreign investor sentiment.

Lee Kyung-min, an analyst at DaishinSecurities, noted, “Amid ongoing tensions between the U.S. and Iran, compounded by the attacks on Saudi Arabian energy facilities, international oil prices continued to rise, while trade tensions between the U.S. and Canada also heightened policy uncertainty.” He added, “Risk appetite weakened in the afternoon as concerns mounted over the unwinding of yen carry trades—where investors borrow low-interest-rate yen to invest in high-yielding overseas assets—due to the yen’s strength, compounded by caution ahead of the release of U.S. Producer Price Index (PPI) and Consumer Price Index (CPI) data.”

Lim Jeong-eun, an analyst at KB Securities, assessed, “The KOSPI surpassed the 7,000 mark intraday as the upward trend in semiconductor stocks continued from the previous day, but it gave up its gains as profit-taking selling emerged.” She also noted, “Caution stemming from heightened tensions in the Middle East limited the extent of the rise,” and predicted that caution would persist ahead of the release of the U.S. August CPI.