Samsung Electronics and SK Hynix shares slipped in Seoul on Thursday, threatening to interrupt a sharp rebound as investors remained nervous about South Korea’s dependence on the artificial intelligence boom.
In an early trading snapshot, Samsung declined 0.22% and SK Hynix lost 0.93%, while the KOSPI fell 0.68%. Wednesday brought gains of more than 7% for both chipmakers and a 3.29% recovery in the benchmark.
The volatility follows an October sell-off that erased approximately $792 billion from the Korean market through Tuesday.
Despite powerful memory demand, investors remain uncertain about the financing behind future AI orders.
Foreign investors remain the crucial swing factor
Foreign investors sold a net 18.115 trillion won of KOSPI shares between 1 and 20 October, according to Chosun. Samsung accounted for 4.075 trillion won and SK Hynix another 9.966 trillion won of those outflows.
Overseas buyers returned on Wednesday, purchasing about 660 billion won of Korean shares. Their reversal helped lift Samsung 5.67% and SK Hynix 5.81% at the close, but Thursday’s retreat showed how easily confidence could falter.
Mirae Asset Securities executive Seo Sang-young said the direction of the market depended heavily on foreign flows into chipmakers and international oil prices.
Higher energy costs and expensive borrowing complicate the outlook for AI data centres, while profit-taking after Wednesday’s rally adds short-term pressure.
Two chipmakers magnify Korea’s market losses
South Korea’s benchmark lost about 1.05 quadrillion won, equivalent to $792 billion, in market value during October through 20 October.
Samsung and SK Hynix together represent nearly half the KOSPI’s market value. When foreign funds cut exposure to the pair, the effect spreads far beyond semiconductor portfolios. Even small changes in appetite for memory stocks can move the entire benchmark.
The concentration extends to leveraged retail investors. Margin loans secured against the two stocks totalled around 9.2 trillion won at September’s end, according to NICE Investors Service figures.
That borrowing can amplify volatility if falling prices prompt investors to raise cash or reduce positions.
Kyle Rodda, a senior analyst at Capital.com, told Reuters on Thursday that markets were still digesting technology earnings alongside uncertainty over interest rates and geopolitical developments.
His warning captures the wider problem, as strong chip sales provide little immediate protection when investors are reassessing risk across markets.
Earnings must show demand can endure
SK Hynix releases third-quarter results on 28 October, followed by Samsung on 29 October. Investors will focus on high-bandwidth memory sales, pricing, order visibility and guidance for 2027.
They will also seek assurances that customers have not begun postponing orders because of higher financing costs.
Near-term fundamentals remain encouraging. South Korea’s semiconductor exports rose 222.5% by value in the first 20 days of October, reflecting strong prices and demand, although export revenue is not a measure of shipment volumes.
Competition from China’s CXMT and questions surrounding debt-funded AI infrastructure nevertheless leave future profits uncertain.
Kiwoom Securities analyst Han Ji-young warned of further volatility as investors absorbed Wednesday’s gains and mixed US technology results, according to Bloomingbit on Thursday.
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