The South Korean stock market is teetering on a technically precarious edge.

The KOSPI index plummeted nearly 9% on Monday, closing near the 6,800-point level, triggering the seventh circuit breaker since 2026, with combined net selling by foreign and domestic institutional investors exceeding $2.6 billion. If the current support level fails to hold, the next key technical level of 6,500 points will become the market's focal point.

This sharp decline was triggered by Middle East tensions and a sell-off in technology stocks. However, a trading flow report from Goldman Sachs' Korea desk highlighted that the real amplifier of the drop was the rapid deleveraging of newly launched single-stock leveraged ETFs. Related semiconductor 2x leveraged products fell over 30% in a single day, with the resulting passive hedging rebalancing accounting for 62% of domestic institutional net selling.

Chris Cha from Goldman Sachs' Korea desk explicitly stated in the report that today's market action constituted position-adjustment selling, not a structural market top. For investors, the most pressing questions now are whether the 6,800-point level can hold and, if it fails, how much further downside pressure the market might face.

Circuit Breaker Triggered Again, Tech Heavyweights Lead Decline

The KOSPI triggered a first-level circuit breaker during Monday's session, halting trading for 20 minutes, before closing at 6,800 points, breaching the psychological 7,000-point barrier.

The initial catalyst for the morning's decline was escalating tensions between the US and Iran near the Strait of Hormuz. However, the sell-off accelerated due to aggressive position unwinding in highly concentrated technology heavyweight stocks.

Shares of SK Hynix Inc fell 15.4% for the day, while Samsung Electronics Co Ltd declined 10.7%.

The Goldman report specifically emphasized that there were no negative fundamental catalysts for the memory chip industry, nor any earnings estimate downgrades, indicating this sell-off is essentially a position-driven shakeout among index giants, not a signal of deteriorating fundamentals.

Leveraged ETFs Act as Amplifier, Drawing Regulatory Scrutiny

The core driver of this extreme volatility was recently listed single-stock leveraged ETFs.

These products are forced to undertake aggressive gamma hedging rebalancing during market declines, creating a self-reinforcing downward spiral. A 2x leveraged ETF linked to semiconductors fell over 30% in a day, with the chain of liquidations it triggered accounting for 62% of domestic institutional net selling.

Concurrently, South Korea's Financial Supervisory Service Governor, Lee Bok-hyun, held a meeting with CEOs from 20 major asset management companies. He expressed strong concerns about the systemic risks of these products and their "overheated" marketing, calling for enhanced consumer protection.

The Goldman report noted that regulatory focus is expected to center on raising investor eligibility thresholds rather than an outright product ban, with no specific measures yet announced.

Passive Selling Dominates, Long-Term Institutions Stay on Sidelines

Foreign and domestic institutions recorded net sales of $1.13 billion and $1.5 billion, respectively, for the day.

A notable point is that foreign selling was almost entirely passive, with programmatic trading accounting for $1.18 billion of the net outflow.

Observations from Goldman's high-touch trading desk corroborated this characteristic: despite the sharp index drop, institutional block trading activity was surprisingly light. Momentum-driven hedge funds engaged in selective selling, while long-term institutions (LOs) largely remained silent. This flow structure suggests there has been no systemic withdrawal of long-term capital.

6500 Points as the Next Line of Defense

From a technical perspective, the KOSPI's current closing level sits precisely at the 6,800-point support. This level corresponds to a 52-week Fibonacci level and remains within the downward trend channel established since mid-June.

The Goldman report points out that if the 6,800-point support fails, the next immediate support is at 6,500 points. This level corresponds to the 38.2% Fibonacci retracement level from the three-year high, implying an additional 4.5% downside from the current close. Further down lies the 6,100 to 6,000-point range, representing a 10% to 12% decline from Monday's close.

The report also notes that the KOSPI's one-standard-deviation move is 2.8%, but the index has recently shown a tendency to move more than two standard deviations. Therefore, the area around 6,000 points is more likely to constitute a relatively strong support zone. Additionally, the KOSPI's 14-day RSI has fallen to 37.2, approaching oversold territory.

Divergence Between Sentiment and Fundamentals, Goldman Advises Buying Dips

There is a clear divergence between the aggressive selling seen on Monday and institutional investors' fundamental views. According to feedback collected by Goldman's sales team during a roadshow in Singapore last week, the institutional consensus is that the recent pullback has presented a highly attractive risk-reward ratio. Some clients have already begun rebuilding exposure to memory chips.

The core logic of the bullish camp rests on structural equipment shortages, which are expected to delay industry capacity expansion until the second half of 2028, providing fundamental support for the semiconductor cycle. A minority of bears worry about potential average selling price declines in Q4 2026 and the peaking of the HBM4 cycle.

Taking a longer-term view, foreign investors have accumulated net sales of $7.15 billion over the past three months, with 88% concentrated in the technology sector, indicating a significant reduction in global positioning. The Goldman report argues that forward earnings per share estimates have remained resilient during the price correction. It views this sell-off as a liquidity-driven position unwinding, not a structural cycle top. The report advises investors to use this extreme volatility to selectively accumulate high-conviction memory and technology stocks at significantly discounted valuations.

In the short term, mechanical foreign selling has yet to show signs of abating. Domestic institutions are constrained by funding issues, with the National Pension Service continuing its portfolio rebalancing. Although swap funding costs have retreated slightly from their peak, they remain elevated. These headwinds persist for the market. The 6,500-point level is becoming the next true battleground for bulls and bears.