The AI-fueled stock market frenzy in South Korea has transformed into a cautionary tale, exposing the market instability that can ensue when leverage outpaces fundamental value. On Monday, shares of SK Hynix plummeted by a record 15%, compelling managers of leveraged products tied to the stock to offload billions of dollars in holdings. This selling spree triggered a worldwide reassessment of AI valuations, ultimately leading to a broader market sell-off. The wave of selling pressure drove the South Korean Kospi index down by 25% over just three weeks, demonstrating how margin loans, single-stock leveraged ETFs, and concentrated index weightings can combine to amplify market swings in both directions.

As key players in the AI hardware supply chain, SK Hynix and Samsung Electronics collectively account for more than half of the Kospi index’s weighting. With SK Hynix accessing the U.S. market through American Depositary Receipts (ADRs), investors are concerned that market sentiment could shift around the clock between Wall Street and Asia. This dynamic raises the specter of global contagion, as leverage-driven volatility in South Korea’s markets could ripple across borders.