Kospi Plunges Over 9% as AI Mania Unravels: Semiconductor Giants Drag Down Overheated South Korean Market

Kospi Plunges Over 9% as AI Mania Unravels: Semiconductor Giants Drag Down Overheated South Korean Market​

The benchmark Kospi index experienced a sharp downturn on June 23, plunging over 8%, triggering a market-wide circuit breaker. This dramatic sell-off underscored growing concerns that the country's record-setting equity rally had become excessively overheated and vulnerable. The rout was led by semiconductor heavyweights Samsung Electronics and SK Hynix, both of which saw significant losses, erasing billions in market value.

The Korea Exchange temporarily suspended trading for 20 minutes after the Kospi fell 8%. However, the decline intensified once trading resumed, with the benchmark extending its loss to as much as 9.1%. This rapid correction has laid bare the fragility of a market increasingly reliant on momentum-driven buying and optimism surrounding AI-related technology.

Drivers Behind the Sharp Market Correction​

Analysts point to a confluence of profit-taking, stretched valuations, and heightened nervousness regarding the sustainability of the AI-driven technology rally. Ha SeokKeun, Chief Investment Officer at Eugene Asset Management, noted that the selloff appears driven by profit-taking after the recent sharp rally due to an increasingly overbought market state.

Foreign investors led a significant exodus from Kospi shares, selling more than 4 trillion won ($2.6 billion). Conversely, domestic retail investors stepped in to purchase the dip during this period of volatility. Market participants also cited rising unease following a pullback observed across US technology stocks. This weakened investor sentiment prompted concerns that highly valued AI-linked companies could face a broader market correction.

Semiconductor Giants Samsung and SK Hynix Under Pressure​

The performance of the Kospi is intrinsically linked to Samsung Electronics and SK Hynix, as these firms dominate South Korea’s semiconductor sector and are primary beneficiaries of global spending on AI infrastructure. Sk Hynix, a crucial supplier of high-bandwidth memory (HBM) chips for advanced AI systems, had experienced an eight-session surge prior to Tuesday’s plunge.

Earlier in the week, SK Hynix's gains for the year approached 350%, making it a powerful symbol of the market’s AI-driven exuberance compared to Samsung's advancement. Lee Jae Mahn, a strategist at Hana Securities, argued that the valuations had become increasingly difficult to justify. He stressed that for the Kospi to rise sustainably, Samsung's share performance must eventually surpass SK Hynix, given stronger earnings expectations anticipated for the larger chipmaker.

Micron Earnings Signal Crucial Test for Hardware Demand​

Investor focus has now shifted dramatically towards Micron Technology’s quarterly results, which are due later this week and will provide critical clues regarding the current strength of demand for memory chips and AI infrastructure. Dilin Wu, a strategist at Pepperstone Group, stated that "Micron's earnings this week are the real test."

Wu added that a strong print would be a direct read-through signal for Samsung and SK Hynix. This particular metric will determine whether the hardware aspect of the current trade still possesses sufficient momentum to support continued growth in the sector. A solid report could revive confidence across the semiconductor space, while any indication of slowing demand might fuel further selling across Asian technology stocks.

Mounting Concerns Over Market Volatility and Debt​

The June 23 plunge exposed the high degree of volatility present in South Korea's stock market following months of exceptional gains. Leveraged exchange-traded funds linked to both Samsung Electronics and SK Hynix have amplified both gains and losses, drawing increased scrutiny from regulators.

The Financial Supervisory Service Governor Lee Chan-jin stated that authorities are actively considering market stabilization measures to curb potential fallout from sharp swings seen in semiconductor-focused leveraged ETFs. Furthermore, the market's rising dependence on borrowed money has raised significant alarms. Data from the Korea Financial Investment Association showed that margin debt, funds borrowed by investors for stock purchases, climbed to a record 38.5 trillion won this month.

While many analysts view the latest decline as merely a correction within a broader AI-led bull market and not the start of a prolonged downturn, elevated valuations and heavy retail participation suggest volatility is likely to remain high in the coming weeks.