[Edaily Reporter Kim Hyung-il ] The KOSPI closed up more than 3% as major semiconductor stocks, including SamsungElectronics and SK hynix, which recovered to the 250,000-won and 1.5 million-won levels, respectively, showed strong gains. Amid continued buying by both foreign and institutional investors, the price of KOSPI 200 futures surged, triggering the intraday buy-side circuit breaker.

On the 12th, the KOSPI closed at 6,579.04, up 233.51 points (3.68%) from the previous trading day. The KOSPI opened at 6,438.50, up 92.97 points (1.47%), and continued to extend its gains throughout the day. There were 380 gainers (including 3 that hit the daily price limit), 477 losers, and 53 stocks that closed unchanged.

At 11:57 a.m. that day, a buy-side sidecar was triggered on the stock market. At that time, the Mini KOSPI 200 futures had risen 5.13% from the benchmark price of 987.08 points to 1,037.76 points, and this surge persisted for one minute. When a buy-side sidecar is triggered, the validity of buy orders in program trading is suspended for five minutes starting from the trigger time. This was the 47th sidecar triggered so far this year and the 23rd buy-side sidecar.

Foreign investors and institutions, in particular, led the KOSPI’s rise. Foreign investors made net purchases of 2.8357 trillion won, while institutions made net purchases of 527.7 billion won. Retail investors made net sales of 3.1913 trillion won. Combined, the net purchases by foreign investors and institutions totaled 3.3634 trillion won.

Large-cap semiconductor stocks showed particularly strong performance. SamsungElectronics closed at 255,500 won, up 6.68% from the previous trading day, regaining the 250,000-won level. SK hynix also closed at 1,504,000 won, up 5.54%, moving into the 1.5 million won range. #SKSQUARE rose 8.36%, and #SamsungElectroMechanics rose 5.78%.

While large-cap stocks on the KOSPI rose 4.02%, mid-cap stocks gained only 0.07% and small-cap stocks rose just 0.03%. By sector, the electrical and electronics sector rose 5.92% and the manufacturing sector rose 4.53%, leading the index higher. Kang Jin-hyuk, an analyst at Shinhan Investment Securities, noted, “As foreign investors continued their non-arbitrage program buying, large-cap stocks—particularly semiconductors—showed strength, and the after-hours rally following earnings announcements by CoreWeave and Supermicro heightened expectations for AI infrastructure demand.”

Confirmed demand for AI infrastructure in the U.S. also bolstered investor sentiment toward domestic semiconductor stocks. AI cloud provider CoreWeave reported second-quarter revenue of $2.58 billion (approximately 3.6574 trillion won), a 112% increase year-over-year, while its order backlog rose 246% to $104 billion (approximately 147.4304 trillion won). Supermicro Computer also reported a fourth-quarter net profit of $1.17 billion (approximately 1.6588 trillion won), a rise of about 500% year-over-year. Following their earnings announcements, the two companies rose by around 15% and 7%, respectively, in after-hours trading.

In contrast, gains on the KOSDAQ were limited due to a shift in market sentiment toward large-cap stocks. The KOSDAQ closed at 858.91, up 1.07 points (0.12%) from the previous trading day. There were 888 gainers (including 8 that hit the daily price limit), 751 losers, and 83 stocks that remained unchanged.

Semiconductor equipment stocks performed strongly on the KOSDAQ. #JUSUNG ENGINEERING Co.,Ltd. rose 7.14%, #WONIK IPS Co.,Ltd. rose 6.49%, and #EO Technics Co.,Ltd. rose 4.61%. #ECOPRO BM CO., LTD. also rose 4.19%. On the other hand, #Alteogen Inc. fell 3.05%, and #ABL Bio Inc. dropped 2.58%. In terms of KOSDAQ trading volume, retail investors were net buyers of 314.9 billion won, while foreign and institutional investors were net sellers of 162.2 billion won and 147.7 billion won, respectively.

Lim Jeong-eun, an analyst at KB Securities, explained, “Led by large-cap semiconductor stocks, the KOSPI rose for the third consecutive trading day, while the KOSDAQ remained largely flat,” adding, “Amid concentrated buying in large-cap stocks, strength was also seen in sectors such as LGELECTRONICS, cosmetics, and power equipment.”

In fact, #LGELECTRONICS rose by over 12% this week on expectations of a meeting scheduled for this week in Silicon Valley between LG Group Chairman Koo Kwang-mo and NVIDIA CEO Jensen Huang. In the cosmetics sector, #KOLMAR KOREA continued its strong performance, rising by over 22%, while #SILICON 2 Co.,Ltd. rose by over 12%. #ILJIN ELECTRIC also rose by around 17% as its second-quarter operating profit increased by 91% year-over-year, and bargain-hunting buying also flowed into defense stocks.