Kospi Jumps 8% as Samsung Averts Strike, Margin Debt Hits $26B
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- Kospi Composite Index rallied more than 8% to an all-time high on Thursday, with nine separate days of 5%+ gains already recorded in 2026 and a near-200% gain over the past 12 months.
- Samsung Electronics rose 8% and SK Hynix rose 11% after averting a labor strike, with Nvidia CEO Jensen Huang declaring that 'demand has gone parabolic' for memory chips — together those two stocks account for nearly half the index's total value.
- LG Electronics jumped 29% in a single session on Huang's bullish comments about the growth potential of physical AI and robotics.
- Margin debt on the Kospi has reached approximately $26 billion as of Thursday, more than double since the start of 2025 and over five times the $5 billion posted in 2020, according to the Korean Financial Investment Association.
- South Korea now has 105 million active trading accounts among a population of just 51 million, with local press reporting brokerage accounts being opened for children, babies, and senior citizens.
- Foreign investors have sold around $55 billion in Korean shares so far in 2026 according to Goldman Sachs data, while domestic retail investors added $36 billion in inflows since the Iran crisis began, per Société Générale.
- Société Générale's Asian-equity-strategy team warned that 'concentration risks are likely to persist' with two stocks making up almost half the index, noting that margin financing 'point[s] to a rising use of leverage among retail participants.'
Why it matters: The rally masks dangerous fragility: with Samsung and SK Hynix comprising nearly half the Kospi's value and margin debt at $26 billion (vs. $5 billion in 2020), a single policy shock — like the MP's proposed windfall tax that already triggered a 5% drop in hours — could amplify a correction through leveraged retail positions held by a record 105 million accounts.
