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SEOUL, Oct. 27 (Yonhap) -- Seoul shares closed higher Tuesday, led by gains in technology shares, as renewed optimism over artificial intelligence (AI) and falling oil prices boosted risk appetite. The Korean won strengthened against the U.S. dollar.
The benchmark Korea Composite Stock Price Index (KOSPI) gained 168.87 points, or 3.09 percent, to close at 5,638.34.
As the market rallied on strong foreign buying, the Korea Exchange activated a buy-side sidecar at 10:13 a.m., suspending buy orders in program trading for KOSPI-listed shares for five minutes. It was the first such action in four trading sessions.
The measure is triggered when KOSPI 200 futures rise at least 5 percent and remain at that level for one minute or longer.
On Wall Street overnight, the Dow Jones Industrial Average gained 0.28 percent, while the S&P 500 advanced 0.7 percent and the tech-heavy Nasdaq Composite climbed 0.82 percent.
Investor sentiment improved after AI startup Anthropic disclosed strong revenue growth in its U.S. initial public offering (IPO) filing, reigniting enthusiasm for AI-related stocks ahead of major tech earnings and the Federal Reserve's interest rate decision.
Oil prices fell on hopes of easing tensions in the Middle East, following reports of Qatari mediation efforts involving Iran and the United States.
Financial data is shown on a screen in the dealing room of Hana Bank in central Seoul on Oct. 27, 2026. (Yonhap)
Trade volume was light at 183.13 million shares worth 15.29 trillion won (US$11.55 billion), with advancers outnumbering decliners 593 to 274.
Foreigners and institutions bought a net 592.97 billion won and 280.38 billion won, respectively, while individuals sold a net 947.78 billion won.
"Foreigners and institutions snapped up major semiconductor stocks amid renewed investment sentiment over AI, despite lingering macroeconomic concerns," Lee Kyoung-min, an analyst at Daishin Securities, said.
Market bellwether Samsung Electronics gained 4.23 percent to 222,000 won, and chip giant SK hynix increased 5.18 percent to 1.34 million won.
SK Square, the parent firm of SK hynix, jumped 7.67 percent to 828,000 won, and Samsung Electro-Mechanics, an electronics component affiliate of Samsung Electronics, surged 7.42 percent to 1.2 million won.
The Korean won was trading at 1,323.7 won against the U.S. dollar at 3:30 p.m., up 2.3 won from the previous stock session's close.
ejkim@yna.co.kr
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