The global AI rally has driven Samsung Electronics and SK Hynix to record highs this year but exposed structural fragility in the KOSPI. The two stocks now account for a record c.60% of the KOSPI's market-cap weighting, up from roughly 40% two years

2026-06-30

The global AI rally has driven Samsung Electronics and SK Hynix to record highs this year but exposed structural fragility in the KOSPI. The two stocks now account for a record c.60% of the KOSPI's market-cap weighting, up from roughly 40% two years ago. After a sharp sell-off last week, regulators suspended twice KOSPI trading to stabilize markets; plans to launch large-cap options including SK Hynix have been delayed. Reports that retail investors bought Samsung and SK Hynix with borrowed funds raise margin-call risk, and the concentration could prompt institutional de-risking that would amplify downside. Baosheng's head of equity research Mathieu Rashet said recent moves are a clear reminder of concentration risk and that crowded positions make high volatility likely.