Key Points
・On July 13, 2026, South Korea’s KOSPI fell 8.95 percent to close at 6,806.93, its steepest drop since the pandemic and the year’s seventh circuit breaker. SK hynix fell a record 15.37 percent, then, on July 15, the index rebounded 6.24 percent to 7,284.41, triggering a buy-side sidecar in the opposite direction.
・The swings sit on top of a record buildup of borrowed money. Margin debt hit an all-time high of roughly 38 trillion won in June, and the Bank of Korea estimates margin debt, unpaid balances, and leveraged ETF holdings combined reached about 75 trillion won as of the end of May. Samsung Electronics and SK hynix alone account for more than half of KOSPI’s total market capitalization.
・The spread of debt-fueled, concentrated bets is not simply a story of reckless gambling. Wages and savings have fallen too far behind housing prices, and confidence in the national pension has eroded, producing what amounts to a rational response to structural anxiety, one that turns a market cycle into a broader social question.
News
On July 13, 2026, South Korea’s KOSPI closed at 6,806.93, down 8.95 percent from the previous session, its steepest one-day drop since the pandemic. At 1:28pm, trading in all listed stocks was halted for 20 minutes when a circuit breaker was triggered, the seventh of the year. SK hynix fell 15.37 percent to 1,845,000 won, its steepest decline since listing, while Samsung Electronics closed down 10.7 percent. Analysts pointed to profit-taking following SK hynix’s Nasdaq listing, concerns that the memory-chip cycle was nearing its peak, forecasts that April-June operating profit would miss market expectations, and the renewed conflict between the United States and Iran.
SK hynix had listed American depositary receipts on the Nasdaq on July 10, reportedly raising $26.5 billion, the largest US share sale by a foreign company on record. On July 14 in New York trading, those ADRs surged 27.29 percent, opening a premium of more than 50 percent over the Korean-listed shares. A price-target upgrade from Barclays and a softer-than-expected US June consumer price index reportedly fueled the buying. Seoul’s market rebounded sharply the next day: on July 15, KOSPI jumped 6.24 percent to 7,284.41, triggering a buy-side sidecar at the open. SK hynix closed up 8.83 percent and Samsung Electronics up 6.27 percent, while foreign investors were net buyers of 2.34 trillion won.
Beneath the swings, forced liquidations of retail positions have surged. Margin calls tied to unpaid settlement balances, known in Korea as forced sales, totaled 425.8 billion won cumulatively between July 1 and 10, including a single-day record of 142.2 billion won on July 9. Margin debt balances had already hit a record 38.4786 trillion won as of June 23.
Financial Supervisory Service Governor Lee Chan-jin made an unusual admission on June 22, saying single-stock leveraged ETFs, approved just weeks earlier on May 27, had “only benefited brokerages.” The next day, KOSPI fell a record 9.99 percent, a drop of 910 points. On the morning of July 15, financial regulators briefed President Lee Jae-myung, who instructed the head of the Korea Exchange and other officials to quickly prepare supplementary measures for single-stock leveraged ETFs. As of July 15, attention has shifted to how far the unwinding of leveraged positions will spread, and whether the regulatory response itself becomes the trigger for the next sharp drop.
Background
“Debt investing”: borrowing from a brokerage to buy stocks
In Korea, buying stocks with borrowed money has its own name: 빚투 (bit-tu), literally “debt investing.” The most common form is margin trading. An investor puts up cash or existing shares as collateral, and the brokerage lends additional funds on top of it, so someone with the equivalent of $1,000 in hand can buy $2,000 or $3,000 worth of stock. If the price rises, the gain is two or three times what it would have been on the investor’s own capital alone.
The trouble shows up when prices fall. The borrowed money does not shrink no matter how far the stock drops. If the value of the pledged shares falls below a set threshold, the brokerage issues a margin call, and if the investor cannot post additional collateral by the deadline, the brokerage sells the shares itself, regardless of the investor’s wishes, to recover the loan. This is the forced sale described above: in the first ten days of July alone, roughly 425.8 billion won of stock was sold this way. A related mechanism applies to unpaid trades, where a brokerage briefly covers a settlement shortfall for three business days; if the gap is not closed by the deadline, the position is liquidated the next trading day regardless of the holder’s wishes.
This kind of borrowing is now at a record scale. Margin debt topped 38 trillion won in June, up more than 10 trillion won in six months from 27 trillion won at the end of last year. Reuters has reported that leveraged investment overall, including margin debt and other borrowed positions, reached a record 60 trillion won as of the end of May. The borrowing is also concentrated: margin debt tied to just two stocks, Samsung Electronics and SK hynix, rose roughly 3.6-fold this year, from 2.53 trillion won at the start of January to 9.1 trillion won.
A new product: the single-stock leveraged ETF
One epicenter of this week’s volatility is a product that barely existed two months ago: the single-stock leveraged ETF, cleared for sale in Korea on May 27. An exchange-traded fund, or ETF, is ordinarily a bundle of many stocks tracking an index, built to spread out risk through diversification. A leveraged ETF applies a multiplier to that bundle, so that if the underlying index rises 3 percent in a day, the fund rises 6 percent. A single-stock leveraged ETF goes a step further: instead of tracking a diversified bundle, it tracks the daily price of one company, such as Samsung Electronics or SK hynix, at double the multiplier. It discards diversification, the one thing an ETF is normally built for, in exchange for a doubled-down bet on a single company.
These products carry a mathematical quirk that punishes volatility itself. Because they reset their multiplier every single day, chasing “twice the day’s move” day after day, a round trip of a sharp fall followed by a rebound leaves behind a loss even after the underlying stock has largely recovered. A simplified example, starting from an index value of 100, illustrates the effect:
| Day 1: down 15% | Day 2: up 13% | Net result | |
|---|---|---|---|
| Underlying stock | 85.0 | 96.1 | roughly a 4% loss |
| 2x leveraged ETF | 70.0 | 88.2 | roughly a 12% loss |
(A simplified estimate applying each day’s percentage change directly; fees and financing costs are not included.)
Even though the underlying stock nearly recovered, the 2x leveraged ETF retained roughly three times the loss. This effect, known as volatility decay, means that in a week like this one for SK hynix, down 15.37 percent on July 13 and up 8.83 percent on July 15, holders who see the underlying stock recover can still find a larger-than-expected loss sitting in their account.
Despite this, money has poured into these products. The combined net assets of the 16 single-stock leveraged ETFs reportedly grew from roughly $3 billion at launch to about $9.1 billion within weeks. Bank of Korea data show that leveraged ETFs overall, including those tracking indexes, held 35.4 trillion won in net assets as of the end of May; combined with margin debt and unpaid balances, roughly 75 trillion won in leveraged money had built up in the market. The central bank has warned that in a downturn, forced sales and ETF rebalancing sales can hit at the same time, deepening losses even for investors who never borrowed a won.
How two stocks came to make up half of KOSPI
This week’s volatility sits on top of a year of record gains. The sequence, laid out chronologically:
– June 2025: Lee Jae-myung takes office as president, having campaigned on eliminating the “Korea discount” and reaching KOSPI 5000
– July 2025: A revised Commercial Act obliging company directors to consider shareholder interests takes effect, restarting the government’s “value-up” push
– End of 2025: KOSPI closes the year at 5,809, up 38 percent, already past the 5000 target
– April 2026: Samsung Electronics and SK hynix together account for 42 percent of KOSPI’s total market capitalization
– June 18: KOSPI tops 9,000 for the first time (9,063.84) on AI-chip optimism; the two stocks’ combined weight rises to 54.4 percent
– June 19: An intraday all-time high of 9,385.59; margin debt tops 38 trillion won
– June 22-23: The FSS governor voices regret over the leveraged ETF approval; KOSPI falls a record 9.99 percent the next day
– July 10: SK hynix lists ADRs on the Nasdaq, reportedly raising $26.5 billion, the largest US listing by a foreign company on record
– July 13: KOSPI falls 8.95 percent to 6,806.93, the year’s seventh circuit breaker
– July 15: KOSPI rebounds 6.24 percent to 7,284.41, a buy-side sidecar triggers, and President Lee instructs regulators to prepare supplementary measures for single-stock leveraged ETFs
Stock indexes weight each company by its market capitalization, so as a stock’s price rises, it automatically claims a larger share of the index. That mechanical effect explains how the two chipmakers’ combined weight rose from 42 percent in April to 54.4 percent within two months. In June alone, retail investors bought a net 16.2 trillion won of KOSPI-listed shares, with 8.4 trillion won of that flowing into Samsung Electronics, even as money flowed out of the smaller-cap Kosdaq index, which fell roughly 7 percent for the month. This was less a broad rally in Korean equities than two stocks lifting the index almost by themselves.
Analysis
When work can’t reach the goal, the market appeared to
What is driving the growth in debt-fueled investing looks less like a taste for risk than a piece of life-planning arithmetic. Japan’s Nikkei has pointed to soaring housing prices and eroding trust in the pension system as the backdrop to Korea’s borrowing boom. Seoul housing prices have moved far out of reach of an average salary, and the timeline for the depletion of the National Pension Service’s reserves has been debated for years. When working and saving no longer seem to add up to a livable retirement, and people the same age are visibly doubling their money in semiconductor stocks, margin trading and leveraged ETFs stop looking like a gamble and start looking like the only ladder left.
The individual cases reported so far read less like thrill-seeking than like fear of being left behind. Reuters described a woman who used a roughly 15-million-won bank overdraft to buy a leveraged Samsung Electronics product, watching a 20 percent unrealized gain turn into a 17 percent unrealized loss, and a housewife who found SK hynix’s own shares too expensive and bought the 2x ETF instead. Nikkei reported on a man in his 40s who borrowed money without telling his wife, saying he did not want to miss the rally everyone else seemed to be riding.
Structure alone does not decide the outcome, though. Facing the same housing prices and the same pension anxiety, the large majority of Korean households are not borrowing to buy stocks. The structure pushes people strongly toward leverage, but the final step remains an individual choice, and it is on that overlap between structure and choice that the next question, where regulation ends and personal responsibility begins, actually sits.
Record highs that make non-participants feel poorer
What makes this rally unusual is that it turned even people who never bought a share into losers. Korean media have carried a steady stream of retail-investor complaints: the market is at an all-time high, but my account is negative; whether or not you happened to hold SK hynix is what decided your return this year. Korean has a word for this: 벼락거지 (byeorak geoji), a portmanteau combining 벼락 (a lightning bolt, used here to mean “sudden”) and 거지 (“beggar”). Coined during the 2020-21 asset boom, it describes someone whose income and savings have not changed at all, but who feels suddenly poor because everyone who happened to hold assets got rich overnight. The past year, in which two chip stocks dragged the entire index upward, reproduced exactly the condition the word was invented to name.
Once that dynamic takes hold, participating in the market stops being a choice to grow one’s money and becomes closer to an obligation not to fall behind. The Bank of Korea specifically warned about latecomer investors chasing the rally out of fear of missing out, and deepening their reliance on leverage as they do. Margin debt hit its record just days before the crash, after the index had already reached the 9,000 range; the later an investor arrives, the higher the price they pay, and the more leverage it takes to capture the same gain.
On the way down, the same mechanism runs in reverse. Accounts that cannot cover a margin call get sold automatically, and that selling triggers further declines and further margin calls elsewhere. The 425.8 billion won in forced sales recorded in early July is the sound of that reverse cycle starting up. On rising days, fear of missing out pulls in new participants; on falling days, forced liquidation culls the ones already in. Neither entry nor exit tracks an individual’s own read of the market, and it is that feature, more than the size of any single day’s move, that turns this from an ordinary market cycle into a social problem.
A government that primed the pump can’t quietly turn off the tap
South Korea’s government has been one of the designers of this rally, not a bystander to it. President Lee Jae-myung was elected on a promise to reach KOSPI 5000, pushed through a Commercial Act revision and a “value-up” campaign that drew in foreign capital, and has treated the rising index as evidence of his administration’s success. Regulators approved the single-stock leveraged ETFs themselves. Given all that, the FSS governor’s unusual admission that the approval was hasty and mostly benefited brokerages carries real weight, but the market’s answer the next day was a record 9.99 percent crash. By July 15, the same president who campaigned on KOSPI 5000 was the one instructing officials to prepare measures to cool it down.
That is the regulatory dilemma laid bare. In a market this dependent on borrowed money, even signaling an intent to tighten rules is enough to trigger anticipatory selling and forced liquidation ahead of the rule actually taking effect. When officials speak, the market falls; when they stay quiet, the leverage keeps building. It is the same underlying problem, unwinding leverage after the fact, that amplified China’s 2015 stock market crash and that Japan’s property-lending caps ran into on the way to the 1990 bubble collapse. Regulators have already imposed two hours of mandatory investor education, a minimum deposit of 10 million won, and limits on margin and unpaid trading before granting access to these leveraged ETFs, and are reportedly considering raising the deposit threshold further. But stronger measures floated by some lawmakers, such as delisting the products outright, risk becoming the very shock that forces a wave of ETF liquidation sales.
Regulators have a defensible case of their own to make, too. Financial authorities and the central bank had warned of overheating before the leveraged ETFs even launched, and had they moved to restrict access earlier or more forcefully, they would likely have faced accusations of paternalistically blocking ordinary people from a wealth-building opportunity. The right moment to close a tap the government itself opened tends to be visible only in hindsight, once it has already passed.
The same structure is already taking root elsewhere
The starting conditions behind Korea’s borrowing boom are not unique to Korea; what differs elsewhere is how far the process has run. Japan has made “from savings to investment” a national policy goal, using tax-advantaged accounts to steer household money into the market, and the same housing-price growth and pension anxiety that motivate Korean investors are present there too. Japanese retail money has fortunately gone mostly into diversified vehicles, world-index and US-index funds, rather than borrowed bets on two domestic stocks, putting real distance between Japan’s pattern and Korea’s.
That diversification has a blind spot of its own, though. A world-index fund and a US-index fund are both weighted by market capitalization, which means that as a handful of giant technology stocks rise, they automatically claim a larger share of both funds. Owning several funds is not the same as being diversified if they all end up holding the same names in the same proportions. The Korean setup, where investors thought they were buying the whole KOSPI and ended up concentrated in two chipmakers, differs in scale and in the use of leverage, but shares the same structural logic that is built into index investing itself. The fact that Nikkei-linked leveraged ETFs remain some of the most heavily traded products on the Tokyo Stock Exchange shows Japanese households are not entirely insulated from the same one-directional crowding. Financial educator Manabu Tauchi has argued that a “you’ll lose out if you don’t start now” tone has crept into financial education and advertising in Japan, crowding out the more basic question of what the investment is actually for.
The lesson worth carrying out of Korea is not that investing itself is dangerous. It is that a government nurturing a genuinely promising industry, and a household betting on that same theme repeatedly, through index funds, direct shares, margin debt, and leveraged ETFs all at once, are two different things. That SK hynix is a globally competitive company in AI memory chips, and that a household that borrowed money to bet on its stock came through this week unscathed, are two separate questions.
Conclusion
What happened in Korea’s market this July does not reduce to a story of individuals driven by greed getting what they deserved. In a society where the ordinary ladder of working and saving no longer reaches housing or a secure retirement, the government paved a road toward the market, the financial industry supplied high-multiplier vehicles to travel it fast, and record index highs broadcast, every day, the relative poverty of anyone not riding along. Each participant behaved rationally within their own position, and the sum of those rational choices made the whole system more fragile. That combination is why this problem will not stay confined to one country, or to one turn of the market cycle.
The volatility may not be over: roughly 38 trillion won in margin debt still has to unwind, and the shape of new regulation is still being worked out. But the question that will outlast whichever direction the market moves next sits with the ladder itself. If a life plan built on working and saving no longer adds up, closing one leveraged product through regulation will only send the same money looking for the next one. Cooling an overheated market is one task. Reducing the reasons people feel they have no real choice but to rush into it is another. Of those two tasks now facing Korea, the second one looks like homework that other countries, Japan very much included, cannot claim as someone else’s problem.
Reference Links
- KOSPI tumbles below 7,000 in ‘Black Monday’ sell-off｜The Korea Times
- KOSPI closes near 7,300 as SK hynix ADR surge boosts investor sentiment｜The Korea Times
- Margin debt hits record as retail investors pile into Samsung Electronics, SK hynix｜The Korea Herald
- SK hynix ADR Jumps 27% in U.S., Signaling KOSPI Rebound?｜Seoul Economic Daily
- SK Hynix Nasdaq debut: $26.5 billion ADR listing sets record｜Yahoo Finance
- “I Want to Make Some Money Too”: As KOSPI Rallies, Retail Investors’ Margin Debt Hits an All-Time High｜Financial News
- Korea regulator blasts Samsung, SK Hynix leveraged ETFs as brokerages reap windfalls｜KED Global
- Fasten your seat belts: Korea’s chip titans turn Kospi into roller coaster｜KED Global
