Key Takeaways
The core driver of the KOSPI plunge was not simply fading expectations for AI semiconductors, but the way leveraged products used by retail investors amplified those expectations at excessive speed.
According to the WSJ report, the KOSPI fell about 40% over six weeks in June-July 2026, erasing roughly $2.5 trillion in market capitalization from the Korean equity market. What this really shows is that share-price moves in Samsung Electronics and SK hynix have now become powerful enough to shake the index, ETFs, and margin balances all at once.
What Happened
The Wall Street Journal, in a report dated August 24, 2026 local time, identified the Korean stock market as one marked by extreme volatility. Riding the AI boom, the KOSPI had more than tripled over the past year before falling about 40% over six weeks in June-July 2026. As of August 25, it had rebounded about 20% from its low, but swings continued.
Single-stock leveraged ETFs are exchange-traded products designed to track a multiple of the daily price change rate of individual shares such as Samsung Electronics or SK hynix. After these products appeared in Korea in May 2026, participation by retail investors increased, and during the downturn, losses expanded faster than those of the underlying assets.
Losses were concentrated among retail investors. Domestic retail investors account for 60-70% of daily trading value, and the WSJ cited cases including an English teacher who lost $19,000 and an audio engineer who invested part of his severance pay in semiconductor stocks and lost $7,200 in a week.
Background and Context
Explaining this market solely through the semiconductor cycle captures only half the picture. Samsung Electronics and SK hynix represented expectations for AI memory demand and lifted the KOSPI’s multiple, while the market assigned a higher value to the growth narrative than to interest rates. The problem was that when expectations began to wobble, leveraged liquidation pressure moved before cash could exit.
Strong market leaders lift an index. But in a market where those leaders carry a heavy weight, single-stock leveraged ETFs and margin trading can spread declines across the broader index. When foreign investors reduce risk and retail investors buy the rebound, losses can be transferred before true price discovery takes place.
Impact on Markets and Stocks
- SK hynix: This is the stock (ticker) that most directly reflected expectations for AI memory. The WSJ reported a case in which an investor in a leveraged ETF linked to SK hynix suffered losses of about 70%, meaning volatility itself, more than share-price direction, eroded investment performance.
- Samsung Electronics: As the flagship stock of the Korean market, it became an underlying asset for single-stock leveraged ETFs. When Samsung Electronics shares wobble, index ETFs, leveraged products, and retail margin positions are affected at the same time.
- Securities industry: A 60-70% retail share of trading is supportive for brokerage commission revenue. In a sharp drop (plunge), however, risks from unsettled trades and margin lending, along with investor-protection regulation, come back as costs.
- KOSPI index: The fact that the index rebounded about 20% from its low after falling about 40% over six weeks points less to recovery than to lingering volatility. It may not be that share prices have truly risen, but that forced-selling pressure has briefly paused.
Investor Checkpoints
- Shift to foreign net buying: Investors need to watch whether foreign selling stops in Samsung Electronics and SK hynix. Without a recovery in foreign investors’ supply-demand (order flow), retail rebound buying will struggle to support prices for long.
- Margin loans and forced liquidation: If margin balances do not decline when the KOSPI tests its lows again, the downturn becomes a liquidation event rather than a price correction.
- Trading value in single-stock leveraged ETFs: If ETF trading is hotter than trading in the underlying stocks, it signals that the market is betting on volatility rather than earnings.
- AI semiconductor order flow: If HBM and memory demand are not confirmed in Samsung Electronics’ and SK hynix’s next quarterly earnings, multiple recovery will be limited.
Outlook
The optimistic scenario is clear. If AI server investment holds up and both memory prices and shipments at Samsung Electronics and SK hynix remain resilient, the KOSPI can recover part of its sharp drop (plunge). In that case, demand to recoup losses in leveraged ETFs could further amplify a short-term rebound.
The trigger for the opposite scenario is also clear. If concerns over slowing AI demand or Chinese memory competition grow again, and the KOSPI falls back toward its June-July lows, retail margin positions will turn from buying capacity into selling pressure. What the market has not yet fully priced in is not so much a slowdown in semiconductor profits as the possibility of tighter regulation on leveraged products.
The next triggers are the Korea Exchange (KRX) and financial regulators’ plans for managing leveraged ETFs, as well as the next earnings releases from Samsung Electronics and SK hynix. If the won-dollar exchange rate sees a sharp gain (surge) and foreign selling resumes, the rebound market could turn into a defensive battle in a single day.
Frequently Asked Questions
Why did the KOSPI plunge 40% in six weeks?
The KOSPI fell about 40% over six weeks in June-July 2026 as expectations for AI semiconductors weakened. In a market heavily weighted toward Samsung Electronics and SK hynix, a correction in the leading stocks spread into a broader index decline.
Leverage magnified the decline. Single-stock leveraged ETFs and retail margin trading turned volatility in the underlying shares into larger gains and losses, amplifying selling pressure.
Why are single-stock leveraged ETFs risky?
Single-stock leveraged ETFs track a multiple of the daily return of individual shares such as Samsung Electronics or SK hynix. In rising markets, returns can be amplified, but in falling or sideways markets, losses and volatility costs accumulate quickly.
In the WSJ report, an investor in a leveraged ETF linked to SK hynix recorded a loss of about 70%. The long-term competitiveness of the underlying company and the short-term profit-and-loss structure of a leveraged product are not the same story.
Can Samsung Electronics and SK hynix shares rise again?
A recovery in Samsung Electronics and SK hynix shares will gain traction when AI memory demand, foreign investors’ supply-demand (order flow), and easing leveraged liquidation pressure are confirmed together. A rebound from the lows alone is not enough to conclude that earnings are recovering.
If memory prices and shipments hold up in the next earnings reports and foreign net buying returns, the quality of the rebound will improve. Conversely, if slowing AI orders are confirmed, the KOSPI’s multiple will move lower again.
This article is automatically summarized and analyzed based on the original news report. View original article (Maeil Business Newspaper Securities)
