Key facts
- KOSPI fell 2.83% to 5,377.17.
- US tech stocks, including Nvidia and Micron, saw significant losses.
- Oil prices climbed amid supply disruption concerns.
- Samsung Electronics and SK hynix shares declined.
- The Korean won strengthened slightly against the dollar.
South Korean stocks opened sharply lower on Friday, October 23, 2026, as persistent concerns over the artificial intelligence industry and rising oil prices weighed on investor sentiment. The benchmark Korea Composite Stock Price Index (KOSPI) fell 2.83 percent to 5,377.17 in early trading. Overnight, U.S. technology shares experienced significant declines, with Micron Technology, Nvidia, and Intel all posting substantial losses. This weakness in AI and semiconductor stocks spilled over into Asian markets. Adding to the market jitters, oil prices climbed amid worries about potential supply disruptions following renewed attacks by Houthi rebels on key facilities in Saudi Arabia. In Seoul, major companies like Samsung Electronics and SK hynix saw their share prices fall, along with battery maker LG Energy Solution and component affiliate Samsung Electro-Mechanics. The Korean won strengthened slightly against the U.S. dollar.