Preface

Context: South Korea's stock market triggered circuit breakers two days in a row, an unprecedented event in the nation's market history. Single-stock leveraged ETFs tied to Samsung Electronics and SK Hynix magnified losses as their net asset values plunged roughly 25% on intraday moves. Purpose: This article explains what happened, why leveraged ETFs amplified the damage, how investors reacted — including a public protest in front of the National Assembly — and what regulatory changes followed. It aims to clarify the mechanics and the policy debate so readers can understand the risks and the market consequences.

Lazy bag

Key takeaways: leveraged single-stock ETFs tied to Samsung and SK Hynix amplified losses to about 25% after consecutive circuit breakers. Retail investors, many heavily exposed, staged a symbolic protest with funeral wreaths at the National Assembly, demanding that regulators ban or tighten access to these products. Officials debated responsibility and quickly raised margin thresholds to try to curb speculative demand.

Main Body

The South Korean stock market experienced a dramatic and rapid sell-off over July 28–29, when circuit breakers activated on consecutive days for the first time in the country's history. The most affected instruments were leveraged single-stock exchange-traded funds (ETFs) that provide two times daily exposure to individual large-cap semiconductor names, notably Samsung Electronics and SK Hynix. Those ETFs are designed to deliver twice the daily return of their reference stock; that same mechanism also doubles daily losses. Over the two-day episode, net asset values for these leveraged ETFs fell by roughly a quarter, inflicting severe losses on many retail investors.

On July 29, more than 30 white funeral wreaths were placed in front of the National Assembly in Yeouido, Seoul. The wreaths were intended to dramatize retail investors' losses — effectively mourning evaporated account balances — and several banners demanded regulatory action, including calls to abolish single-stock leveraged ETFs. The protest was organized and driven by investors who had incurred heavy losses from these products during the market plunge.

Understanding why these ETFs were so damaging requires a brief look at how they work. Leveraged ETFs rebalance their holdings every trading day to maintain a fixed multiple (in this case, two times) of that day's return of the underlying stock. If the reference share rises 10% in a day, the leveraged ETF seeks to rise 20% that day. Conversely, if the share falls 10%, the ETF aims to lose 20%. Importantly, daily rebalancing introduces a path-dependent drag — sometimes called volatility decay or negative compounding — so repeated intra-day swings can erode an ETF's long-term value even if the underlying stock later recovers its prior price. This effect makes leveraged ETFs particularly risky for investors holding them over multiple days in highly volatile markets.

Public officials delivered mixed messages after the losses. Kim Yong-beom, the head of the presidential policy office who was accompanying the president on a trip to Brazil, emphasized multiple factors — uncertainty about AI investment returns, intensifying global competition in semiconductors, and broader market structure issues — suggesting responsibility should not rest solely on leveraged ETFs. To many retail investors who saw their portfolios shrink by about 25%, such explanations felt like shirking accountability.

By contrast, the head of the Financial Supervisory Service, Lee Chan-jin, publicly expressed regret and acknowledged that regulators might have prevented the product approvals that allowed these leveraged single-stock ETFs to proliferate. His comment amounted to an admission that the regulatory review process had been insufficient in protecting ordinary investors from complex, high-risk products sold through familiar brokerage channels.

Within the ruling party and among lawmakers, debate split into two camps. Some used stark language — labeling the products as speculative "instruments of gambling" — and pushed for an outright removal of such ETFs from the market. Others worried that a sudden delisting could harm market credibility and preferred a regulatory tightening that raised investor barriers, such as increasing margin requirements to limit speculative inflows.

The immediate regulatory response was decisive: effective July 31, new or additional purchases of single-stock leveraged ETFs require a minimum margin deposit of 30 million Korean won (roughly tens of thousands of U.S. dollars, depending on the exchange rate). Regulators estimate this step will reduce overall trading volume in leveraged ETFs by more than half and sharply cut new account openings for these instruments. The measure aims to curb retail speculation by making access more costly.

However, raising the margin threshold mitigates the scale of participation but does not change the structural mechanics that produce large losses during volatile periods. The three essential features that generate systemic risk in this context are: 1) fixed daily leverage (two times); 2) daily rebalancing; and 3) negative compounding through repeated intra-day volatility. These same structural traits have been implicated in large losses in other markets and products, such as perpetual futures in cryptocurrency markets. Leveraged ETFs differ mainly in appearance: they are regulated, listed products distributed through broker channels, and therefore may appear less hazardous to unsophisticated retail investors than explicitly labeled derivative contracts.

Timeline matters. Regulators’ internal doubts about approving these products were reportedly raised as early as June. In mid-July, authorities temporarily halted reviews of new leveraged ETF listings, but the higher margin requirement did not take effect until the end of July — after the market shock and investor losses had already occurred. The delay highlights a recurring theme in financial regulation: oversight often reacts to crises rather than preventing them.

South Korea’s large base of retail investors gives this episode political significance: their collective voting power can shape how fast and how far lawmakers move to change product rules, disclosure requirements, and investor eligibility. Possible next steps include further lowering allowable leverage ratios, restricting which investors can buy leveraged products, mandating clearer warnings and investor suitability checks, or even delisting the riskiest offerings.

For retail investors and policymakers alike, the episode is a clear reminder to align product design, distribution practices, investor education, and supervisory safeguards. Leveraged single-stock ETFs can be useful tactical instruments for sophisticated traders with short horizons and a clear understanding of day-to-day rebalancing mechanics. But when sold widely through retail channels without adequate protections, they can become a conduit for concentrated speculative risk — and a flashpoint for social and political backlash when markets turn.

Key Insights Table