AI Bubble Bursting? South Korea's Kospi Crashes 7% Amid AI Stocks Valuation Concerns

South Korea's Kospi suffered a sharp selloff on Tuesday as investors reassessed the durability of the artificial intelligence-led rally that has powered the country's largest chipmakers. The benchmark index dropped more than 6.6% during the session, with Samsung Electronics and SK Hynix at the centre of the decline.

The fall was significant because the two semiconductor companies carry unusually high weight in South Korea's equity market. Samsung Electronics and SK Hynix together account for more than half of the Kospi index, making broader market performance highly sensitive to shifts in sentiment around memory chips and AI infrastructure spending.

Chip stocks drag Kospi lower as AI doubts grow

The Kospi was down 505 points, or 6.62%, at 7,522.84 during the session at 9:27 am. The scale of the move triggered a "sidecar" trading curb, a mechanism that temporarily suspends programme trading when market moves become unusually sharp. Such curbs are intended to reduce disorderly trading during periods of high volatility.

Samsung Electronics fell 7.47%, even after projecting a 19-fold increase in second-quarter operating profit from a year earlier. The company's profit estimate was stronger than its combined profit over the previous three years, helped by record memory chip prices linked to surging demand for AI hardware.

SK Hynix, another major supplier of advanced memory products used in AI servers, declined 6.70%. The company has benefited from demand for high-bandwidth memory, a key component used in graphics processing units and data centre systems built for generative AI workloads.

The selloff showed that strong earnings alone may no longer be enough to support valuations. Investors are now asking whether the pace of AI-related orders can continue, and whether chip prices have already reflected the most optimistic demand assumptions.

Why the AI trade matters for South Korea

South Korea's stock market has been one of the clearest global expressions of the AI investment boom. As technology companies and cloud providers expand data centre capacity, demand has risen for specialised chips, memory modules and advanced computing systems. Korean manufacturers occupy a central place in that supply chain.

That exposure has helped the Kospi outperform other major global indices in 2026. The index remains up 76% so far this year, driven largely by investor enthusiasm for companies linked to AI infrastructure. For global funds, South Korea has become a direct way to participate in the semiconductor cycle.

However, the same concentration has created a vulnerability. When confidence in AI-linked earnings weakens, the impact spreads quickly across the index. A fall in Samsung Electronics and SK Hynix can outweigh gains in many smaller companies, leaving the broader market exposed to a narrow investment theme.

Foreign investors also added pressure by continuing to sell South Korean equities. They offloaded shares worth 1.3 trillion won, or about $851.45 million, during the session. Persistent foreign selling often amplifies domestic market declines, especially in large-cap technology stocks with deep institutional ownership.

Losses spread beyond Samsung and SK Hynix

The weakness was not limited to semiconductors. Battery maker LG Energy Solution dropped 6.77% after saying its April-June operating profit is expected to fall 77%. The company cited continued weakness in electric vehicle demand, which has weighed on battery sales across the global supply chain.

Shipbuilder Hanwha Ocean slumped 22.91% after Canada selected German submarines instead of South Korean competitors in an ongoing contract contest. The steep fall reflected disappointment over a major defence opportunity at a time when investors have been closely tracking global shipbuilding and defence orders.

Automakers were also under pressure. Hyundai Motor lost 6.57%, while affiliate Kia Corp fell 5.66%. Steelmaker POSCO Holdings declined 3.27%, and Samsung BioLogics slipped 0.57%. Among 910 traded stocks, 357 advanced and 511 declined, showing that the selloff was broad but led by index heavyweights.

Concerns around the semiconductor sector were further sharpened by reports that Apple is in discussions to source chips from two Chinese semiconductor manufacturers. Any shift in sourcing patterns could raise questions about competitive pressure on established suppliers, although the long-term commercial impact remains unclear.

For investors in India, the move is relevant beyond South Korea. AI-linked technology stocks have influenced global risk appetite, including flows into Asian markets. A sharp reversal in Korean chipmakers can affect sentiment toward technology-heavy indices, semiconductor suppliers and companies tied to data centre expansion.

The Kospi's decline does not by itself mark the end of the AI investment cycle. It does, however, underline how quickly markets can reprice when expectations become stretched. South Korea's dependence on a small group of semiconductor giants means its benchmark index will remain highly sensitive to any change in the AI demand outlook.