Patrick Boyle
July 18, 2026
South Korea's Stock Market Paradox: Bull and Bear at Once
TL;DR
South Korea's stock market achieved record gains driven by semiconductor giants Samsung and SK Hynix, but extreme leverage and retail speculation created a dangerous crash that wiped out hundreds of thousands of investors.
Key Takeaways
- 1The KOSPI rose 76% last year and 112% by June 2024, making it the world's best performer, yet has since crashed 27% into a bear market—both extremes driven by the same underlying forces
- 2Two companies, Samsung and SK Hynix, account for nearly 60% of the index, creating concentration risk so severe it forces foreign funds to sell due to diversification rules
- 3Korean retail investors ('ants') drive ~50% of trading volume and poured $80 billion into the market as foreign investors fled, banking on AI chip demand continuing indefinitely
- 4Leveraged ETFs promising 2x daily returns amplified volatility mechanically through forced daily rebalancing, with rebalancing trades representing two-thirds of SK Hynix volume on volatile days
- 5Over 1.2 million retail accounts faced margin calls during the crash; roughly 360,000–400,000 were fully liquidated, with many owing money to brokers after positions gapped through maintenance levels
- 6The Korean won weakens despite record trade surplus because chip earnings stay offshore and retail savers export savings to buy US tech stocks, creating currency pressure and inflation
- 7The entire bull case rests on four American hyperscalers (Amazon, Google, Meta, Microsoft) maintaining massive AI infrastructure spending; any slowdown in capex would crater chip demand and trigger a memory industry collapse
Notable Quotes
“The Cosby isn't really a diversified basket of a nation's industry. It's a leverage bet on two chip stocks wearing the country as a costume.”
“Looking back, I regret not doing everything I could to stop it.”
— Head of the Financial Supervisory Service
“Even when handed an edge, people don't bet calmly. They bet too big.”
“The way up was a choice that millions of people made. The way down if it comes won't ask anyone's permission.”
Chapters
1. The Paradox: Best and Worst Market Simultaneously
The KOSPI rose 76% in 2023 and 112% by June 2024, becoming the world's best-performing market, yet has crashed 27% since peaking. The index is simultaneously a generational bull market for those who entered early and a devastating bear market for those who joined near the top or used leverage.
2. Samsung and SK Hynix: The Two-Stock Index
These semiconductor giants achieved 756% and 405% operating profit gains respectively due to AI boom demand. By June, they comprised 60% of the KOSPI (up from 40% eighteen months prior), making the index essentially a leveraged bet on two chip stocks rather than a diversified economy.
3. The Retail Army: Financial Nihilism and Theme Stocks
14 million retail 'ants' account for ~50% of Korean trading volume versus 20% in the US. Priced out of housing and facing bleak career prospects, young Koreans view leverage not as reckless but as the only viable path to wealth. This echoes Korea's historical 'theme stock' culture, exemplified by DIC Corp rising 800% when CEO's son released 'Gangnam Style.'
4. Leveraged ETFs: The Microphone-to-Speaker Feedback Loop
Korean brokerages launched 16 leveraged ETFs promising 2x daily returns on Samsung and SK Hynix. These funds mechanically rebalance daily—buying strength, selling weakness—creating a short-gamma dynamic. On turbulent days, rebalancing trades comprised two-thirds of SK Hynix volume and forced $5 billion in sales during Monday's crash alone.
5. The Crash: 1.2 Million Margin Calls in Days
As the KOSPI fell 9% in a single session, leveraged ETF rebalancing hit retail investors automatically. Over 1.2 million accounts were margin called; 360,000–400,000 were fully liquidated. Many positions gapped through maintenance levels, leaving investors owing brokers money after their savings evaporated.
6. The Coin-Flip Lesson: Why Leverage Destroys Correct Bets
Psychologist Victor Haggani's experiment showed that 28% of subjects lost everything in a rigged coin-flip game favoring them 60–40, proving that even with odds in your favor, people bet too large and normal variance wipes them out before the edge works. Korean retail investors were right about Samsung and SK Hynix but didn't survive the leverage.
7. The Currency Trap: Dream Dollars and the Weak Won
Korea's record trade surplus should strengthen the won, but chip export earnings stay offshore via 'dream dollars'—funds kept abroad for overseas expansion. Meanwhile, retail savers buy US tech stocks, forcing currency sales. The weak won raises import costs and inflation, forcing rate hikes into a falling market.
8. Regulatory Contrition and Too-Little-Too-Late Measures
The Financial Supervisory Service head admitted 'I regret not doing everything I could to stop it.' New rules freeze leveraged ETF listings and require $20,000+ accounts plus risk training—measures that arrived after the damage was done and do little to address underlying structural risks.
9. The Hidden Risk: Hyperscaler Spending and Commodity Chips
The entire bull case depends on Amazon, Google, Meta, and Microsoft maintaining massive AI capex spending. But TSMC's recent earnings miss on margin concerns signals the market is questioning whether AI models generate enough revenue to justify continued infrastructure spending. If hyperscalers slow capex, chip demand collapses—hitting a two-stock index hard.
10. What Happens If AI Becomes a Commodity
AI labs subsidized usage with flat-rate pricing; this is shifting to metered, usage-based pricing. If AI pricing collapses toward marginal cost like electricity, value flows to users, not infrastructure builders. Hyperscalers would reduce capex, memory chip prices would cliff-dive, and leveraged Korean ETFs would amplify the collapse mechanically.
Key People & Entities
- President Lee Junggun (implied 'Lee Jung-uh')
- South Korea's president who campaigned on raising the KOSPI to 5,000; presided over it peaking at 9,000 but now faces falling markets
- Samsung Electronics
- Major global semiconductor manufacturer; 30% of KOSPI weight; 756% operating profit surge driven by AI chip demand
- SK Hynix
- World's second-largest memory chip maker; 30% of KOSPI weight; 405% operating profit surge; subject of Hong Kong leveraged ETF fund worth $13 billion
- Owen Lamont
- Academic portfolio manager at Harvard, Princeton, Chicago, Yale; warned that US market is 'Koreafying' into retail-driven theme stock chasing
- Brad Setzer
- Economist who coined term 'dream dollars' to describe chip export earnings kept offshore rather than repatriated
- Victor Haggani
- Psychologist who conducted famous coin-flip experiment proving people bet too large even with favorable odds, causing bankruptcy despite edge
- Sy (esim app sponsor)
- Mobile eSIM service provider offering data plans across 200+ destinations; offering 15% discount through video link
- MSCI
- Company that classifies markets as 'developed' or 'emerging'; still files South Korea as emerging due to restricted won convertibility
Glossary
- KOSPI
- Korea Composite Stock Price Index, South Korea's main stock market benchmark
- Ants
- Korean retail investors, analogous to 'apes' in the Western Wall Street Bets community; roughly 14 million strong and account for ~50% of trading volume
- Theme stocks
- Korean investment concept where retail investors bet on stocks based on thematic narratives (e.g., CEO's famous son) rather than business fundamentals
- Leveraged ETF
- Exchange-traded fund that uses derivatives to deliver 2x daily returns; mechanically rebalances daily by buying strength and selling weakness, amplifying volatility
- Short gamma
- Risk dynamic where a hedger is forced to sell into falling prices and buy into rising prices, amplifying moves; analogous to audio feedback
- Margin call
- Broker demand that investor deposit additional funds or liquidate positions when account value falls below maintenance requirement
- Total return swap (TRS)
- Derivative where investment bank agrees to pay fund a multiple of daily stock returns in exchange for fee; bank hedges by trading actual shares
- Credit Line Extension (CLE)
- Exotic derivative purchased by banks to insure against leveraged fund default; cost reflects market anxiety about gaps in leverage products
- Dream dollars
- Chip export earnings (notably from Samsung and SK Hynix) kept offshore rather than repatriated, suppressing domestic currency demand
- Hyperscalers
- Large cloud infrastructure companies (Amazon, Google, Meta, Microsoft) investing hundreds of billions annually in AI data center capex