KOSPI tops 3,600 on AI chip surge

The KOSPI surpassed the 3,600 mark for the first time on Oct. 10, setting its 11th record high of the year. Shares of Samsung Electronics and SK hynix surged on expectations of an AI-driven semiconductor supercycle, driving the rally.

On the first trading day after the Chuseok holiday, the index rose above 3,600 early in the session and closed at 3,610.60, up 61.39 points, or 1.73 percent, from the previous day. It climbed as high as 3,617.86 during the session, setting all-time intraday and closing records. The benchmark had first broken through 3,500 just one trading day earlier, on Oct. 2.

Pent-up optimism from the five-day holiday boosted semiconductor shares. Samsung Electronics rose 6.07 percent to close at 94,400 won, while SK hynix jumped 8.22 percent to 428,000 won. Including preferred shares, Samsung’s market capitalization reached 619.4 trillion won, surpassing 600 trillion won for the first time. SK hynix’s market value rose to 311.6 trillion won, also exceeding 300 trillion won.

Foreign investors bought more than 1 trillion won in local stocks after global tech firms, including Nvidia, OpenAI and AMD, announced major AI infrastructure investments during the holiday. Institutional investors sold 594.5 billion won, while individual investors offloaded 502 billion won.

Despite some warnings of an AI-driven bubble, analysts say the semiconductor supercycle appears to have begun. Supply shortages are expected not only for advanced chips such as high-bandwidth memory (HBM) but also for NAND flash, boosting profit prospects for Samsung and SK hynix.

Nuclear power stocks also rose on expectations of higher demand from AI data centers. Doosan Enerbility jumped 14.97 percent, HD Hyundai Electric gained 5.6 percent, and Hyosung Heavy Industries climbed 6.09 percent.

Outside AI-related stocks, the broader market weakened. On the KOSPI, 277 stocks advanced while 624 declined. LG Energy Solution fell 9.9 percent, and Hanwha Aerospace dropped 5.01 percent as secondary battery and defense stocks underperformed


홍석호 will@donga.com