320,000 Koreans Wiped Out: How Single-Stock Leveraged ETFs Turned an AI Rally Into a National Apology

South Korea's finance minister had to apologize to the nation.

Not for a currency crisis. Not for a bank failure. For a product design decision: allowing retail investors to buy 2x leveraged ETFs on individual Korean stocks — then watching more than 320,000 of them lose everything when the AI-memory rally reversed.

Fernando Sánchez's reconstruction of the episode is a case study in how euphoria, concentration, and leverage compound.

The Setup: A Market That Became Two Stocks

Between December 2025 and June 2026, the KOSPI rose approximately 130%. Korea's equity market jumped from outside the world's top 20 to roughly the 6th largest on the planet.

The fuel was AI memory. The two global leaders in HBM — the high-bandwidth memory required for AI processing — are Korean: SK Hynix and Samsung. By late June, those stocks were up on the order of +970% and +500% year to date.

The structural risk was already visible before any product launch: those two companies alone represented more than 50% of the entire KOSPI. An "index" that concentrated was already a single-theme bet dressed as diversification.

The Detonator: Single-Stock Leverage Approved in May

Until May 2026, Korean retail investors were prohibited from trading leveraged products on domestic individual stocks. The government considered them too dangerous.

Then the rules changed — not because the products became safer, but because capital was fleeing to the United States, where Koreans could already buy leveraged ETFs on American companies. To stem that outflow, the Korean regulator approved leveraged ETFs linked to major domestic names, including SK Hynix and Samsung.

Sixteen new ETFs marked the shift from broad-index leverage to concentrated single-stock bets.

Retail responded exactly as product designers should have feared. Korean individual investors put roughly $9.7 billion into the new leveraged vehicles, chasing the euphoria of past gains. Fernando's line is blunt: the most dangerous product in the market ended up, almost entirely, in the hands of the least prepared investors.

At the KOSPI's historical highs around June 22, the total market capitalization of these new leveraged ETFs peaked near $52.5 billion.

The Unwind: Arithmetic, Not Opinion

Then memory stocks corrected.

Between June 22 and July 30:

• SK Hynix: -54%
• Samsung: -43%

The two names that were half the index fell together. The leveraged ETFs — designed to amplify every move — did what they are built to do:

• SK Hynix 2x ETF: approximately -80% from peak
• Samsung 2x ETF: approximately -75% from peak

The KOSPI had no escape hatch. It fell roughly 40%.

According to Goldman Sachs, about 1.2 million investors received margin calls — requirements to post more cash to cover losses. That is roughly 3.5% of Korea's entire adult population. More than 320,000 suffered a complete liquidation. They lost everything.

A week before Fernando's note, the finance minister convened an emergency meeting with the Bank of Korea governor and the top securities regulators, apologized in parliament, and admitted the ETFs should not have launched without deeper prior study.

Contagion Beyond Seoul

The Korean collapse did not stay local. The US semiconductor complex absorbed the aftershock:

• SMH (US semiconductor index): about -25% from June 22 to July 30
• Nasdaq: about -7%
• Micron (MU): about -39%
• SanDisk (SNDK): about -55%

Investment banks now believe the wave of forced liquidations has largely run its course. The decline was about flows and excess leverage. Semiconductor stocks have since strung together several up sessions.

That does not rewrite the human ledger. Three hundred twenty thousand Korean accounts were wiped out along the way.

The Formula

Fernando closes with the equation that made the outcome predictable:

Euphoria + extreme concentration + leverage + investors without training = guaranteed disaster.

Each term was necessary. Euphoria filled the products. Concentration meant there was no diversification inside the "index." Leverage turned a severe correction into an extinction event for retail accounts. Lack of preparation meant participants discovered the product's math only after the margin call.

The lesson is not that AI memory was a fraud. SK Hynix and Samsung remain central to the HBM supply chain. The lesson is that a legitimate industrial boom, wrapped in a national index that is really two stocks, then wrapped again in 2x single-name ETFs sold to retail, becomes a financial weapon aimed at the people least equipped to survive volatility.

Korea did not need a banking crisis to produce a national apology. It needed a product launch timed to the peak of a narrative.

---

This analysis is based on Fernando Sánchez's Telegram commentary on the South Korean leveraged ETF crisis, August 2026. For informational purposes only — not financial advice.