South Korea’s Kospi fell 16.19% in October, sliding from 6,838.04 to 5,730.74, according to financial industry figures reported by the Busan Ilbo. The retreat was the index’s seventh-largest monthly percentage decline on record and left investors facing another sharp reversal in an unusually volatile year.
The index rose on only eight of October’s 20 trading days. On declining sessions, the average loss was 3%, exceeding the 2.44% average gain recorded on rising days. That imbalance meant intermittent rebounds were not strong enough to offset the month’s heavier selloffs.
AI spending fears overwhelmed chip earnings
Concerns about artificial intelligence investment weighed on sentiment. Credit worries surrounding US neocloud company CoreWeave, together with weaker cash-flow trends at Meta, Alphabet and Amazon, fueled expectations that technology companies could slow AI spending. Strong results from Samsung Electronics and SK Hynix did not overcome those concerns.
October was the third exceptionally weak month for the Kospi in 2026. The index’s seven largest monthly declines include three from this year: 22.19% in July, 19.08% in March and 16.19% in October. Three 2026 results also rank among the six largest monthly gains, showing that the turbulence has moved sharply in both directions rather than following a single downward path.
Trading safeguards have been activated with similar frequency. The securities market recorded 55 sidecar triggers in 2026, the most since statistics under the current standard began in 2002 and more than double the 26 recorded in 2008. A sidecar pauses program trading orders for five minutes when Kospi 200 futures remain at least 5% above or below their reference price for more than one minute. Continuing AI investment concerns and upcoming results from major technology companies could keep short-term volatility elevated.