The KOSPI opened more than 1% higher on hopes for South Korea-U.S. artificial intelligence (AI) cooperation, but staged a roller-coaster session, repeatedly swinging between gains and losses due to a supply-demand shock stemming from the listing of Chinese DRAM maker CXMT. Foreign investors sold nearly 3 trillion won on a net basis, but the index closed higher as institutions and retail investors stepped in to buy on dips.
According to the Korea Exchange on the 27th, the KOSPI ended at 6,755.75, up 65.13 points, or 0.97%, from the previous trading day. The index opened higher at 6,806.27, up 115.65 points, or 1.73%, but quickly turned lower as foreign selling widened, at one point falling to 6,557.39 during the session.
By investor type, foreigners were net sellers of 2.885 trillion won on the main bourse alone. Retail investors and institutions absorbed the supply, buying 1.98 trillion won and 862.3 billion won, respectively. Foreigners posted large-scale selling for a second consecutive session, after offloading 3.2683 trillion won worth of shares on the 24th of this month.
Top market-cap stocks showed a mixed performance. Samsung Electronics (1.80%), SK hynix (3.24%), Samsung Electronics preferred shares (1.52%), LG Energy Solution (1.06%), Hyundai Motor (0.50%), Samsung Biologics (1.78%) and KB Financial (0.64%) closed higher. In contrast, SK Square (-1.17%), Samsung Electro-Mechanics (-0.08%), Samsung Life Insurance (-2.04%) and Samsung C&T (-0.73%) traded weaker.
The domestic market opened higher on the day, supported by large-scale cooperation plans announced by Korean companies including Samsung Electronics and SK hynix with global big tech firms such as Nvidia, Broadcom, Microsoft (MS) and OpenAI at the "San Francisco AI Summit" held over the weekend, despite a sharp drop in U.S. semiconductor stocks. Investor sentiment was also underpinned by a stabilization in international oil prices and U.S. Treasury yields as military tensions between the United States and Iran eased somewhat.
However, supply-demand instability from the CXMT listing overwhelmed the positive factors during the session, widening volatility centered on semiconductor stocks. The market views this as the effect of the listing of Chinese memory chipmaker CXMT drawing in global investment funds during the session. CXMT listed on the STAR Market of the Shanghai Stock Exchange on the day, forming an opening price of 49.50 yuan, 471.6% above its offering price of 8.66 yuan, before surging to 55.03 yuan during the session. Its market capitalization surpassed 3.6 trillion yuan (about 778 trillion won) intraday, becoming the largest by market cap on China's mainland stock market, while its trading value also exceeded 120 billion yuan (about 26 trillion won), a record high for a single A-share stock.
"Even though tensions from the Middle East eased and large-scale cooperation projects with big tech were announced, volatility from CXMT grew," said Kang Jin-hyuk, a researcher at Shinhan Investment Corp. "Amid rising to the No. 1 spot in A-share market cap immediately after listing, overtaking ICBC, supply-demand effects before and after the market open also affected the Korean stock market." Lee Kyoung-min, a researcher at Daishin Securities, also noted, "Solid AI investment and expanded collaboration with global companies acted as an upward force on related sectors," while pointing out that "the upward momentum of domestic semiconductor stocks was limited by the impact of the CXMT listing."
Meanwhile, the KOSDAQ index closed at 764.86, up 16.64 points, or 2.22%, recovering from the previous session's sharp decline (-5.32%). Retail investors and foreigners were net sellers of 144 billion won and 129.5 billion won, respectively, but institutions alone bought 272.7 billion won, lifting the index. In addition, all of the top 24 stocks by market capitalization closed higher.
