The KOSPI climbed more than 3% to reclaim the 5,600 level, lifted by news that U.S. artificial intelligence company Anthropic is pursuing an initial public offering. Samsung Electronics (005930.KS) and SK hynix (000660.KS) both surged, pushing the index past 5,700 at one point during the session. The benchmark pared some of those gains, however, as caution set in ahead of major corporate earnings and the U.S. Federal Open Market Committee meeting.
The KOSPI closed at 5,638.34 on the 27th, up 168.87 points, or 3.09%, from the previous trading day, according to the Korea Exchange. The index had fallen 1.46% to 5,469.47 a day earlier, but opened at 5,658.65 on the 27th, up 189.18 points, or 3.46%, and triggered a buy-side sidecar — a temporary halt on program-trading buy orders — for the first time in four sessions. It later retreated to the mid-5,600s as profit-taking emerged.
Foreign and institutional investors drove the advance. On the main board, foreign investors bought a net 590.9 billion won and institutions a net 282 billion won, while retail investors sold a net 949.2 billion won to lock in profits. Foreign investors bought both spot shares and futures on a net basis for the first time in four sessions, breaking a recent selling streak. Institutional buying weakened in the afternoon, however, slowing the index's rise.
Among the largest stocks by market capitalization, chipmakers led the gains. Samsung Electronics closed at 222,000 won, up 4.23% from the previous session. SK hynix rose 5.18% to 1.341 million won. SK Square (402340.KS), which holds a stake in SK hynix, gained 7.67%, while Samsung Electro-Mechanics (009150.KS) rose 7.42%, Samsung Life Insurance (032830.KS) 3.45% and LG Energy Solution (373220.KS) 2.00%. Samsung Biologics (207940.KS) bucked the trend, falling 5.37%.
The KOSDAQ also finished higher, up 16.62 points, or 2.29%, at 743.83. Foreign investors bought a net 24.5 billion won and institutions a net 150.4 billion won, while retail investors sold a net 166.1 billion won. EcoPro (086520.KQ) rose 6.74%, EcoPro BM (247540.KQ) 5.58%, Wonik IPS (240810.KQ) 4.92% and Jusung Engineering (036930.KQ) 4.30%. Alteogen (196170.KQ) ended unchanged.
Behind the rebound in Korean stocks were expectations of improving profitability in the U.S. AI industry. Anthropic said on the 26th that it had filed an S-1 registration statement with the U.S. Securities and Exchange Commission to pursue a Nasdaq listing. Its revenue in the first half of this year came to $16.286 billion, up about 1,300% from the same period a year earlier. Its operating loss narrowed to about $693 million from $2.14 billion over the same span. Confirmation that demand for AI services is translating into actual revenue growth improved investor sentiment toward related companies.
Sentiment was further supported by reports that SpaceX is pursuing a financial lease agreement worth about $40 billion to secure Nvidia's next-generation graphics processing units, fueling expectations of wider chip demand. In New York overnight, the Philadelphia Semiconductor Index rose 2.82%, with Micron up 3.0%, AMD 2.8% and Nvidia 2.4%. "Anthropic's disclosure of its registration statement served as a catalyst for a recovery in AI investor sentiment, drawing bargain hunters into Korean semiconductor stocks as well," said Lee Kyoung-min, an analyst at Daishin Securities.
Brokerages say this week's major earnings reports will determine whether the rebound holds. SK hynix's third-quarter results and the possibility of additional shareholder return measures, both due on the 28th, are seen as key variables. Samsung Electronics' final third-quarter results and the FOMC decision are scheduled for the 29th. With funding burdens from expanding AI investment still in place, analysts say capital expenditure guidance from Big Tech companies and improvement in their cash flow will be critical. "If semiconductor earnings and Big Tech guidance are confirmed, there is room for a reversal in high-beta styles such as momentum and size, which fell sharply in October," said Lee Jun-young, an analyst at Eugene Investment & Securities.
