South Korean Shares Plunge to Near an 11-Week Low

The benchmark KOSPI plunged nearly 8% to around 5,540 on Thursday, extending its losing streak to seven sessions and falling to its lowest level since late July, as mounting concerns over AI valuations and financing costs intensified the global tech sell-off. Samsung Electronics and SK hynix tumbled nearly 9% and 11%, respectively, as investors questioned the sustainability of AI spending, tracking losses among US chipmakers. Additionally, hotter-than-expected US inflation, with annual CPI rising to 3.7% in September, fueled concerns over further Federal Reserve rate hikes, raising borrowing costs and weighing on equities. The sharp decline triggered a sell-side trading halt, while foreign investors remained net sellers. Other notable declines included SK Square (-10.1%), Samsung Electro-Mechanics (-14.6%), LG Energy Solution (-4.9%), Hyundai Motor (-6.1%), Doosan Enerbility (-7.8%), Hanwha Aerospace (-2.7%), and Kia Corporation (-3.3%).

The benchmark KOSPI fell 0.44% to close at 6,009 on Wednesday, extending its losing streak to six sessions as renewed concerns over AI spending and a weaker-than-expected sales outlook from ASML erased early gains. The Dutch chipmaking equipment supplier reported strong third-quarter earnings, but its 2026 sales forecast fell short of market expectations, despite its shares having surged 84% over the past year. The disappointing outlook weighed on investor confidence across the semiconductor sector, erasing the KOSPI’s early gains. Investors also remained cautious ahead of US inflation data, which could influence the Federal Reserve’s policy outlook. Losses were recorded in SK hynix (-1.66%), SK Square (-0.58%), Samsung Biologics (-1.99%), Samsung C&T Corp (-2.83%), KB Financial Group (-1.97%), Shinhan Financial Group (-4.71%), Doosan Enerbility (-1.14%), and Hana Financial Group (-2.25%), while Samsung Electronics ended flat.

The benchmark KOSPI rose nearly 1% to around 6,080 on Wednesday, snapping a five-day slide near a more than two-month low, as investors bought semiconductor shares following a sharp selloff in the previous session. Samsung Electronics and SK hynix climbed nearly 2% and more than 1%, respectively, recovering part of Tuesday's plunge of 7.39% and 10.09%. Gains also extended to other heavyweight stocks, including SK Square (1.28%), LG Energy Solution (2.7%), Hyundai Motor (1.1%), Kia Corporation (1.4%), Hyundai Mobis (4.1%), and Samsung Electro-Mechanics (1.7%). Meanwhile, lingering concerns over Chinese chipmaker CXMT's technological advances and the sustainability of AI spending continued to weigh on the sector. Investors also remained cautious ahead of the US September inflation report, with an expected acceleration in consumer prices potentially complicating the Federal Reserve's interest rate outlook and adding to concerns over technology stock valuations.