The combined market capitalization of Samsung Electronics and SK hynix topped 900 trillion won for the first time. With strength in the No. 1 and No. 2 market-cap stocks, the KOSPI index set another all-time high, with 3,750 in sight.
On the 16th, the KOSPI index closed at 3,748.37. It rose 91.09 points (2.49%) from the previous day, rewriting the all-time high in just one day. In the KOSPI market, institutions and foreigners bought a net 741.8 billion won and 652.8 billion won, respectively, leading the index higher. Individuals were net sellers of 1.3937 trillion won.
The semiconductor rally continued amid the artificial intelligence (AI) boom. Samsung Electronics shares ended the day at 97,700 won. They rose 2.84% (2,700 won) from the previous day. They broke past the 96,800 won level recorded in Jan. 2021 and set a new all-time high for the first time in about four years and nine months.
SK hynix shares also finished at 452,500 won, up 7.1% (30,000 won) from the previous day. They climbed as high as 455,000 won intraday, once again renewing the highest price since 2000.
Based on the closing prices that day, the market capitalization of Samsung Electronics and SK hynix stood at 578.3486 trillion won and 329.4211 trillion won, respectively, totaling 907.7697 trillion won. It is a record high, and there are even projections that the combined market capitalization of Samsung Electronics and SK hynix could top 1,000 trillion won.
Global investment bank (IB) UBS evaluated 2026 as "a once-in-a-decade year for memory semiconductors" and set target prices for Samsung Electronics and SK hynix at 112,000 won and 590,000 won, respectively. If actually achieved, their market capitalizations would be 663 trillion won and 430 trillion won, respectively.
Expectations for the conclusion of follow-up Korea-U.S. trade talks also buoyed auto stocks. Hyundai Motor and Kia shares each rose more than 8% and 7% in a single day.
In tandem with aggressive data center investments by U.S. big tech, the secondary battery sector also drew attention. Global electric vehicle sales reached a record-high 2.1 million units in September, stoking investor sentiment.
LG Energy Solution ended trading at 420,500 won, up 8.8% (34,000 won), breaking above the 400,000 won closing level for the first time since November last year.
In contrast to the hot KOSPI index, the KOSDAQ index was sluggish. It closed at 865.41, up 0.69 points (0.08%) from the previous day. In the KOSDAQ market, only individuals went on a "buying" spree of 348.5 billion won. Institutions and foreigners sold a net 236.2 billion won and 96.9 billion won, respectively.
Amid strength in the secondary battery sector, ECOPRO BM and Ecopro shares each jumped more than 14% from the previous day. However, Alteogen, the KOSDAQ market bellwether, as well as Rainbow Robotics, Peptron, and LigaChem Biosciences, showed weakness.
With Presidential Chief of Staff for Policy Kim Yong-beom and Minister Kim Jung-kwan of the Ministry of Trade, Industry and Energy among the Korean government's negotiating team arriving in the United States that day, whether the working-level talks can produce results is expected to shape the short-term market mood. The main agenda items include the method of investing $350 billion in the United States, where the two countries had wide differences, and foreign-exchange market safeguards.