S Korean stocks plunge 4% as DeepSeek's new model sparks chip demand fears. South Korean stocks continued to decline on Monday, as Chinese startup DeepSeek's latest model sparked concerns over lower demand for memory chips. The country's benchmark index, Kospi, dropped as much as 3.2%, while chipmakers Samsung Electronics and SK Hynix dropped over 4% each before paring losses. Notably, the Kospi is coming off its worst weekly performance since October 2008.