The KOSPI climbed nearly 2% to close within reach of the 7,000 mark, lifted by record semiconductor exports and strong earnings from U.S. chipmaker Micron Technology. The KOSDAQ surged more than 4% as biotech, semiconductor and secondary battery shares rallied together. Both indexes opened lower on pressure from rising long-term U.S. Treasury yields before turning higher on earnings optimism, ending in positive territory together for the first time in four sessions.
The KOSPI finished at 6,971.35 on the 1st, up 133.31 points, or 1.95%, from the previous session, according to the Korea Exchange. The index opened 0.34% lower at 6,814.49 before reversing course during the session and widening its gains. The KOSDAQ closed at 894.29, up 38.38 points, or 4.48%, marking a fifth straight session of gains.
Institutions were net buyers of 417 billion won worth of shares on the main board. Retail investors and foreign investors were net sellers of 1.71 trillion won and 336.7 billion won, respectively. On the KOSDAQ, institutions and foreign investors bought a net 570.4 billion won and 327 billion won, while retail investors sold a net 878.8 billion won.
Samsung Electronics (005930.KS) closed at 276,000 won, up 7,500 won or 2.79% from the previous session, while SK hynix (000660.KS) ended at 1.833 million won, up 57,000 won or 3.21%. Both stocks had fallen more than 1% early in the session before rebounding to lead the index higher. Samsung Electronics preferred shares rose 4.76%, Samsung Electro-Mechanics (009150.KS) 3.17%, Samsung Biologics (207940.KS) 2.73%, Hyundai Motor (005380.KS) 1.16% and LG Energy Solution (373220.KS) 0.98%. KB Financial Group (105560.KS) fell 1.66%.
On the KOSDAQ, LEENO Industrial (058470.KQ) jumped 10.90%, while other semiconductor-related shares also advanced, including Wonik IPS (240810.KQ) at 9.13%, EO Technics at 8.46%, HPSP at 8.32% and Simmtech at 6.25%. EcoPro (086520.KQ) and EcoPro BM (247540.KQ) rose 5.58% and 5.13%, respectively, while Rainbow Robotics gained 5.02% and Alteogen (196170.KQ) 4.13%. Advancing issues accounted for 57% of the KOSPI and 67% of the KOSDAQ, indicating the rally spread broadly across the market.
Expectations for the semiconductor cycle underpinned investor sentiment. Micron said revenue for its fiscal fourth quarter, covering June through August, reached a record $54.23 billion (about 73.5 trillion won). Beyond results and guidance that exceeded market forecasts, the company projected that memory supply and demand would be tighter in 2027 and 2028 than this year, fueling expectations of a prolonged supply shortage.
South Korea's chip exports also set a record. Semiconductor exports rose 262.8% from a year earlier to $60.3 billion (about 81.94 trillion won) last month, topping $60 billion for the first time, according to September trade figures released the same day by the Ministry of Trade, Industry and Energy. The gain reflected both higher export volumes and rising contract prices amid expanding memory demand.
"Semiconductor shares rallied as Micron projected that memory supply and demand would be tighter in 2027 and 2028 than this year, while Korean chip exports also hit a record high," said Lim Jung-eun, an analyst at KB Securities. "On the KOSDAQ, biotech, pharmaceutical and semiconductor shares rose together, drawing buying interest that drove the index higher."
