South Korea's stock market has staged a globally eye-catching surge in the first half of the year, yet the internal structure of this rally is raising deepening concerns.

The benchmark KOSPI index soared 101.14% cumulatively in the first six months, ranking first among the world's major stock indices. However, according to data, foreign investors were net sellers of a record 148.3 trillion won in Korean shares during the same period. In contrast, individual investors were net buyers of approximately 99.2 trillion won, with institutions purchasing a net 35 trillion won, positioning retail investors as the primary force absorbing the foreign sell-off.

This dynamic of "foreign capital flight and retail investors stepping in," coupled with the explosive growth of leveraged ETFs, is building systemic risks beneath the market's calm surface. A recent report describes the KOSPI's trajectory as "a massive, self-reinforcing feedback loop" and warns that Asia-centric, particularly Korean, leverage demand is pushing the entire leverage chain toward its limit.

Dual Drivers of Foreign Exodus: Rebalancing and Currency Pressure

The large-scale retreat of foreign investors is not without reason. Market observers widely believe the KOSPI's rapid ascent itself provided the direct trigger for foreign selling.

As the weight of Korean stocks in global portfolios expanded significantly due to the price surge, foreign investors faced rebalancing pressure, needing to actively reduce holdings to maintain predetermined asset allocation ratios. One analysis points out that "the increase in the market value of foreign holdings corresponding to the KOSPI index far exceeded the index's own rise, with its proportion in the overall index reaching its highest level since the financial crisis." The view is that the trend of persistent foreign net selling is unlikely to reverse until the KOSPI's upward momentum slows noticeably.

Currency factors have further intensified the selling意愿. Since May, the won has steadily weakened against the US dollar, depreciating by approximately 66.1 won from 1483.3 to 1549.4 over two months. To avoid foreign exchange losses, foreign investors net sold 92.9 trillion won during this period, accounting for over 60% of the total net sales for the first half.

One analyst warns that the potential stock of shares foreigners could still sell is "estimated to be no less than the amount sold so far," and expects a strong US dollar and continued foreign securities sales to push the won higher in the second half, potentially touching 1580, though a retreat to the 1400 range is anticipated after the fourth quarter.

Retail Investors' High-Leverage Catch: A Vulnerable Feedback Loop

While foreign capital continues to exit, Korean retail investors, with nearly 100 trillion won in net purchases, have become the market's primary support, with a significant portion of that exposure amplified through leverage tools.

Leveraged ETF products were the standout stars of the Korean market in the first half. Data shows the top 12 ETFs by performance were all leveraged products—those tracking twice the daily return of their underlying index. The "TIGER 200IT Leverage" ETF led with a staggering 764.07% gain, followed by the "KODEX Semiconductor Leverage" and "TIGER Semiconductor TOP10 Leverage" with gains of 493.80% and 361.23%, respectively.

A single-stock leveraged ETF for SK hynix Inc listed on May 27 also performed remarkably, with its post-listing gains occupying the top seven spots in recent performance rankings.

However, the flip side of this leverage feast is sharply amplified market volatility. A researcher notes that "with the rapid expansion of domestic and international ETF markets, the influence of leveraged ETFs has continuously increased, structurally elevating stock market volatility." The analyst also cautions that "while leveraged ETFs amplify volatility, the direction of stock prices ultimately aligns with earnings, and a shift from concentrated holdings to a broader portfolio should now be prepared for."

Warning Sign: The Leverage Chain Nears Its Limit

The leverage behavior of retail investors is not an isolated phenomenon but a highly sensitive node in the global leverage system.

A trading expert warns in a recent report that the financing rate for September-expiring S&P 500 Total Return Futures (SPX TRF) spiked to a high of the Federal Funds rate plus 127.5 basis points last Friday, with dealer leverage reaching historically high mid-year levels. The expert directly attributes this abnormal rise to "insatiable" demand for leverage from Asia—particularly South Korea.

Follow-up reports indicate the explosive growth of leveraged ETF products, the expansion of retail margin accounts, and a surge in hedge fund deposits at prime brokers have jointly driven an unusual mid-year jump in market funding costs, now at their highest level since December 2024. A brokerage executive states, "Leverage has become one of the most central themes for investors right now, with margin debt high and borrowing across all parts of the shadow banking system continuing to expand."

The report also characterizes the KOSPI's movement as "a massive, self-reinforcing feedback loop"—rising stock prices attract more leveraged money, which further pushes prices higher, creating a cycle. The core concern is that once dealer financing spreads become untenable for a counterparty, leading to a sudden liquidity tightening, the entire leverage chain could rapidly unwind in reverse, risking a cliff-like drop in asset prices.

Institutions Raise Targets Amid Growing Risk Divergence

Despite the flashing risk signals, domestic Korean brokerages remain optimistic about the second-half market outlook, primarily citing continuously improving earnings expectations for semiconductor companies.

Two major securities firms have raised their second-half KOSPI target upper bounds to 11,000 points, with another setting a target of 11,500 points. An analyst at another firm notes, "Individual investors are concentrating their purchases in semiconductor ETFs, and the earnings momentum for memory semiconductor companies continues, with relatively low valuation pressure. Preference for semiconductor ETFs is expected to persist in the near term."

However, one firm also acknowledges that expectations for foreign inflows from events like the listing of an SK hynix ADR and Korea's inclusion in a global bond index, "considering the absolute size and the inflow time window, are still unlikely to offset the persistent net selling trend of foreign investors in the domestic stock market."

Against the多重 backdrop of high leverage, continuous foreign outflows, and currency pressure, the sustainability of this rally, led by retail and leveraged funds, faces increasingly severe tests.