Chip Stocks Slide as Kospi Falls 5.5%

South Korean memory-chip stocks plunged on October 13, pulling the Kospi sharply lower as investors weighed concerns about AI-related valuations, competition and the durability of chip profits against strong demand for memory products. Samsung Electronics shares closed down 7.4% and SK Hynix fell 10.1%. Over the five trading sessions through October 13, the stocks had lost about 16% and 22%, respectively. The Kospi ended the day 5.5% lower, after dropping more than 7% intraday. Samsung and SK Hynix together account for about half the index’s weight, magnifying the effect of their declines. The selloff followed a weak session for U.S. technology stocks and reports about progress by Chinese memory maker ChangXin Memory Technologies, known as CXMT. CXMT said it had advanced a memory-cell design intended to store more data in less physical space and plans to introduce a server memory product based on it by the end of 2026. The development raised questions about future competition, though analysts cited in reporting said CXMT still faces technical hurdles in advanced high-bandwidth memory.