On October 15, 2026, the KOSPI index dropped 7.57% to close at 5,554.22, marking its lowest level since April. The decline was driven by investor skepticism regarding the profitability of heavy investments in AI infrastructure.
Samsung Electronics shares fell by 9.5%, while SK Hynix declined by 11% on the same day. Currently, SK Hynix is trading approximately 35% below its peak, and Samsung is down about 22% from its high.
The KOSPI index has fallen roughly 40% from its June 2026 peak of 9,386. Trading activity triggered circuit breakers on multiple days, including October 15, due to the intensity of the sell-off.
Market pressure stemmed from higher-than-expected US inflation data, financial distress in AI sectors, and disappointing revenue forecasts from companies like OpenAI and Anthropic.
Foreign investors sold billions of dollars in Korean shares throughout October 2026. Additionally, the AI-focused firm Elice saw its shares drop 32% on its market debut on October 20, 2026.
Despite the recent downturn, the KOSPI index remains up approximately 30% year-to-date, following a 116% surge earlier in 2026 fueled by enthusiasm for the semiconductor and AI industries.
