KOSPI Surges, Buy-Sidecar Triggered During Session...Samsung Electronics and SK hynix Jump Over 7%

Foreign Investors Buy KRW 2.5 Trillion, Institutions Net KRW 0.9 Trillion on KOSPI
Electrical and Electronics Sector Including Samsung Electronics and SK hynix Jumps 7%
KOSDAQ Remains Flat Overall, Semiconductor-Related Stocks Rise

The KOSPI index surged more than 4% during trading hours, driven by strong buying from foreign and institutional investors, triggering a buy-sidecar (temporary suspension of program buying orders). The top two stocks by market capitalization, Samsung Electronics and SK hynix, each saw gains of over 7%.

On the 12th, the KOSPI index opened at 6438.5, up 92.9 points from the previous trading day, with the domestic stock market status displayed on the electronic board in the dealing room of Hana Bank in Jung-gu, Seoul. On the same day, the KOSDAQ index opened at 854.85, down 2.99 points from the previous trading day. August 12, 2026. Photo by Kang Jinhyung

As of 12:44 p.m. on August 12, the KOSPI index was trading at 6,635.51, up 289.98 points (4.57%) from the previous trading day. Earlier, around 11:57 a.m., the KOSPI 200 futures index on the Korea Exchange rose 50.68 points (5.13%) from the previous session’s close, activating the buy-sidecar.

The upward momentum continued from the opening, fueled by foreign and institutional buying. Foreign investors posted net purchases totaling 2,484.51 billion won, and institutions recorded net purchases of 901.16 billion won. In contrast, individual investors recorded net selling of 3,169.94 billion won.

By industry, the gains in the electrical and electronics sector (+7.13%), which includes Samsung Electronics and SK hynix, stood out. The manufacturing sector (+5.49%), financials (+2.40%), insurance (+2.40%), construction (+2.21%), and securities (+2.11%) also showed strong performance. Meanwhile, pharmaceuticals (-2.76%), non-metals (-1.27%), and food & tobacco (-1.86%) sectors declined.

Among the top stocks by market capitalization, semiconductor stocks such as Samsung Electronics (+7.7%) and SK hynix (+7.0%) stood out. Other notable gainers included SK Square (+10.7%), Doosan (+7.6%), Samsung Electro-Mechanics (+6.1%), Samsung Life Insurance (+5.8%), Samsung SDI (+5.3%), and Hanwha Aerospace (+5.1%). On the other hand, HD Korea Shipbuilding & Offshore Engineering (-4.2%), Meritz Financial Group (-3.5%), and Hyundai Mobis (-3.5%) declined.

Meanwhile, the KOSDAQ index was trading at 857.78, down 0.06 points (0.01%) from the previous trading day. In terms of investor type, individuals posted net buying of 310.64 billion won, while foreigners and institutions recorded net selling of 159.94 billion won and 137.64 billion won, respectively.

By industry, non-metals (+6.26%), distribution (+3.41%), machinery and equipment (+1.99%), and chemicals (+1.59%) were strong. However, pharmaceuticals (-1.65%), food & tobacco (-1.41%), and entertainment & culture (-1.06%) sectors showed weakness.

Alteogen, the largest stock by market capitalization on KOSDAQ, fell more than 3% (-3.2%), while the second and third largest stocks, Ecopro (+0.6%) and Ecopro BM (+2.0%), were either flat or gained. Semiconductor-related stocks such as Jusung Engineering (+7.2%) and Wonik IPS (+6.4%) also showed strong performance. In contrast, bio stocks like Samchundang Pharm (-3.5%), Ligachem Bio (-1.5%), and Caregen (-1.5%) declined.

Seokhwan Kim, a researcher at Mirae Asset Securities, said, "After the close of the U.S. stock market, both CoreWeave and Super Micro Computer reported strong earnings, confirming robust demand for artificial intelligence (AI) infrastructure, which appears to have improved investor sentiment toward domestic semiconductor stocks."

This content was produced with the assistance of AI translation services.