South Korean stocks tumbled over 4% on Wednesday amid growing concerns about an artificial intelligence bubble, mirroring a sharp decline on Wall Street. The KOSPI index fell 135.79 points, or 3.29%, within the first 15 minutes of trading, slipping below the 4000-point mark after a week of gains. Leading the downturn, Samsung Electronics dropped 4.29%, SK Hynix fell 4.78%, and both Hyundai Motor and Hanwha Aerospace saw declines exceeding 3%. The sell-off in South Korea followed a negative session in the U.S., where major indexes closed lower. Blue-chip tech stocks, including Nvidia and Palantir, were hit hard by fears of overvaluation in the AI sector. Wall Street executives have suggested that the market may need to pull back before achieving further gains.