The South Korean stock market has suffered a severe setback, driven not by a deterioration in fundamentals but by a forced liquidation of positions ignited by leveraged products.

According to the Goldman Sachs trading desk, Chris Cha, a sales trader at the firm's Seoul office, noted in a market observation report dated July 14th that the KOSPI plummeted 9% that day to close at 6,800, triggering a circuit breaker for the seventh time since 2026. The core driver of this decline was the concentrated deleveraging of newly listed single-stock leveraged ETFs, rather than any negative fundamental signals or earnings downgrades. Foreign and domestic institutional investors combined for a net sell-off exceeding $2.6 billion on the day.

What's Driving the Plunge

Notably, the reaction from net long-only institutional investors was unusually muted amid the index's sharp fall, with block trading activity surprisingly low. Goldman Sachs views this decline as a "liquidity-driven position washout," not a structural signal of a cyclical top, and advises investors to use the extreme volatility to accumulate high-conviction exposure to memory chips and technology stocks.

The Unwinding of Single-Stock Leveraged ETFs

The immediate trigger for the KOSPI's plunge was escalating Middle East tensions—specifically, the ongoing U.S.-Iran friction near the Strait of Hormuz—but what amplified the losses was the concentrated unwinding of positions in recently listed single-stock leveraged ETFs.

According to Chris Cha's report, semiconductor-linked 2x leveraged ETF products fell over 30% on the day, forcing massive gamma rebalancing operations that created a downward spiral. This mechanism accounted for 62% of the net selling by domestic institutions that day. SK Hynix Inc and Samsung Electronics Co Ltd fell 15.4% and 10.7% respectively, yet neither company had any negative fundamental catalyst or earnings forecast downgrade, indicating the selling was entirely driven by positioning factors.

Regulators responded swiftly. The head of South Korea's Financial Supervisory Service, Lee Chan-jin, convened a meeting with the CEOs of 20 major asset management firms on the same day, expressing strong concern over the systemic risks and "overheated" marketing of such products and calling for enhanced consumer protection. The regulatory focus is now expected to center on raising product entry barriers, rather than an outright ban, with specific measures yet to be announced.

Fund Flows: Passive Foreign Selling, Long-Only Institutions on Hold

In terms of fund flows, both foreign and domestic institutions were net sellers on the day. Foreign investors net sold $1.3 billion, with programmatic trading accounting for $1.18 billion of that, almost entirely passive selling. Domestic institutions net sold $1.5 billion, concentrated mainly in ETF-related liquidations.

Observations from the Goldman Sachs desk corroborate this passive-dominated market dynamic: despite the dramatic index decline, institutional block trading activity was surprisingly subdued. The report notes that visible active selling on the day came primarily from momentum-driven hedge funds, while net long-only institutions remained silent.

Over the past three months, foreign investors have accumulated net sales of KOSPI shares totaling $71.5 billion, with 88% concentrated in the technology sector, indicating global investors have significantly reduced their positioning in the Korean market.

Technical Outlook: Key Support Under Threat

From a technical perspective, the KOSPI closed precisely at the 6,800 level—the 52-week Fibonacci support. The index has been operating within a clear downtrend channel since mid-June and has now reached a critical technical inflection point.

If the 6,800 support fails, the next support level is at 6,500 (approximately 4.5% below the day's close), corresponding to the 3-year 38.2% Fibonacci retracement. The next zone below that is the 6,100 to 6,000 range, representing a decline of about 10% to 12% from the day's close. The report notes that while a one-standard-deviation daily move for the KOSPI is 2.8%, recent intraday swings have frequently exceeded two standard deviations, increasing the probability of testing the latter support zone. Additionally, the KOSPI's 14-day RSI has fallen to 37.2, approaching oversold territory.

There is a clear divergence between this market plunge and institutional investors' fundamental assessment. According to feedback collected by Goldman Sachs' sales team during a roadshow in Singapore last week, institutional investors broadly believe the previous correction had restored the risk-reward profile of Korean tech stocks to highly attractive levels and were already in the process of rebuilding exposure to memory chips.

The core logic of the bullish camp centers on: structural equipment shortages expected to delay industry capacity expansion until the second half of 2028, and forward earnings per share estimates remaining robust despite significant price corrections. A minority of bearish voices express concerns over potential Average Selling Price (ASP) declines in Q4 2026 and the risk of the HBM4 cycle peaking.