Seoul:Seoul shares experienced a significant surge, climbing over 6 percent on Wednesday, driven by a substantial rally in chipmakers. This increase followed SK hynix's report of record quarterly earnings and an announcement of additional shareholder returns. The Korean won, however, weakened against the U.S. dollar.
According to Yonhap News Agency, the benchmark Korea Composite Stock Price Index (KOSPI) rose by 374.1 points, or 6.63 percent, closing at 6,012.44, having reached a peak of 6,032.28 during the day. In response to the strong market rally led by tech gains, the Korea Exchange activated a buy-side sidecar just before 11 a.m., briefly suspending program trading buy orders for KOSPI-listed stocks.
Earlier in the day, SK hynix reported its highest-ever revenue and operating profit for the third quarter, driven by strong memory chip demand amid the ongoing artificial intelligence (AI) boom. The company, the world's second-largest memory chip maker, also announced a shareholder return program exceeding 100 trillion won (US$75.3 billion) for 2026.
Investors were keeping a close watch on the Federal Reserve's impending interest rate decision, set for early Thursday (Korean time), as they sought indications regarding the future trajectory of U.S. interest rates.
In the trading room of Hana Bank in central Seoul, financial data was displayed after the stock market closed on October 28, 2026. Trade volume was relatively light, with 223.2 million shares valued at 19.83 trillion won, and advancers outnumbering decliners 580 to 288.
Foreign investors and institutions purchased a net 815.83 billion won and 960.79 billion won, respectively, while individual investors sold a net 1.8 trillion won. Analyst Lee Jae-won from Yuanta Securities highlighted that SK hynix's performance demonstrated the potential for AI chip demand to result in substantial operating profits and shareholder returns, alleviating concerns about the sustainability of the AI-driven rally and a potential peak in the memory chip cycle.
Significant gains were observed among market heavyweights. Samsung Electronics, the top market cap, rose 9.01 percent to 242,000 won, while chip giant SK hynix saw a 10.89 percent increase to 1.49 million won. SK Square, the parent company of SK hynix, advanced 11.23 percent to 921,000 won, and Samsung Electro-Mechanics surged 8.74 percent to 1.3 million won.
The Korean won was trading at 1,337.7 won against the U.S. dollar at 330 p.m., a decline of 10.7 won from the previous session's close. Bond prices, which move inversely to yields, closed lower, with the yield on three-year Treasurys gaining 4.1 basis points to 3.799, and the return on the benchmark five-year government bonds increasing by 5 basis points to 3.949.