The day after the KOSPI’s biggest-ever rally, the market staged a sharp reversal on Aug. 3, triggering overheating warnings across the leveraged ETF (exchange-traded fund) market. According to South Korea’s Financial Supervisory Service (FSS) electronic disclosure system, 195 ETFs disclosed premium dislocation from the previous session’s close as of 9:30 a.m. — equivalent to 16.8% of all 1,155 ETFs listed.

The premium rate measures the percentage difference between an ETF’s market price and its net asset value (NAV). A premium dislocation means the ETF traded away from its underlying value, a frequent occurrence during market overheating. Among the products flagged this time were eight single-stock leveraged and inverse ETFs tracking Samsung Electronics and SK Hynix — half of the 16 such products in existence. The breakdown: five SK Hynix leveraged ETFs, two Samsung Electronics leveraged ETFs, and one inverse ETF.

Notably, Mirae Asset Management’s TIGER SK Hynix Single Stock Leverage ETF disclosed a premium dislocation. Mirae Asset said the fund closed at a market price of ₩9,445 (approximately $6.61), trading 1.52% above its indicative NAV (iNAV) of ₩9,302.83. “The dislocation occurred during the closing single-price auction in the final 10 minutes of trading (3:20 p.m.–3:30 p.m.), creating a positive premium,” the firm explained. It added: “The premium is a temporary phenomenon. On the following trading day, we will provide ample liquidity quotes to narrow the gap, allowing investors to trade normally.”

An industry insider said, “As the KOSPI surged by its largest margin in history, premium dislocations on some single-stock leveraged ETFs widened temporarily. In particular, buy orders increased sharply just before the close, pushing market prices above NAV in many cases.”

The KOSPI plunged on Aug. 3 as profit-taking flooded in following the previous session’s historic surge. As of 11 a.m., the index was down 275.32 points (4.17%) at 6,320.13, having fallen as much as 5% intraday. On July 31, the KOSPI had soared 1,001.89 points (17.91%) — the largest single-day percentage gain and point rise in its history.

The whipsaw action extends a roller-coaster stretch that began July 28. That day, the KOSPI crashed 10.84% on a semiconductor selloff, triggering both a sell-side circuit breaker and sidecar. It fell another 5.98% on July 29. On July 30, the index attempted to reclaim the 6,000 level but closed 1.23% lower on retail selling. Then came the 17.91% record rebound on July 31, followed by the 4%-plus pullback on Aug. 3 — five consecutive sessions with moves of 5% or more in absolute terms.

On the main bourse, foreign investors and institutions sold a net ₩1.66 trillion (approximately $1.2 billion) and ₩898.2 billion (approximately $628.3 million), respectively, dragging the index lower. Retail investors, meanwhile, bought a net ₩2.49 trillion (approximately $1.7 billion). Foreign investors also held a net sell position of ₩337 billion (approximately $235.7 million) in KOSPI 200 futures.

Among large-cap stocks, semiconductor names led the decline: Samsung Electronics fell 7.81% and SK Hynix dropped 8.09%. SK Square (-2.60%), LG Energy Solution (-3.81%), and Samsung Biologics (-3.03%) also declined. Bucking the trend, Samsung Electro-Mechanics rose 4.12%, Hyundai Motor gained 0.90%, and Shinhan Financial Group added 0.99%, showing clear sector divergence.

Stock% ChangeNoteSK Hynix-8.09%Gave back prior day’s limit-up (+29.95%)Samsung Electronics-7.81%Pullback after +26.81% surgeLG Energy Solution-3.81%Samsung Biologics-3.03%SK Square-2.60%Samsung Electro-Mechanics+4.12%Only semiconductor-related gainerShinhan Financial Group+0.99%Hyundai Motor+0.90%

Hong Kong-listed leveraged ETFs tracking Korean semiconductor stocks also tumbled in tandem. The CSOP SK Hynix 2x Leveraged ETF (07709) fell 14.16% to HK$36.50 (approximately ₩6,700), while the CSOP Samsung Electronics 2x Leveraged ETF (07747) dropped 11.72% to HK$68.38 (approximately ₩12,000).

While the KOSPI corrected, the KOSDAQ market attracted rotational buying and pushed higher. The KOSDAQ index was up 29.38 points (4.08%) at 749.14 as of the same time, briefly touching 752.00 intraday and triggering a buy-side sidecar. Retail and institutional investors bought a net ₩67.1 billion (approximately $46.9 million) and ₩51.2 billion (approximately $35.8 million), respectively, while foreign investors sold a net ₩122.6 billion (approximately $85.8 million).

Market (as of 11 a.m. Aug. 3)ForeignInstitutionalRetailKOSPI-₩1.66T-₩898.2B+₩2.49TKOSPI 200 Futures-₩337B–KOSDAQ-₩122.6B+₩51.2B+₩67.1B

The contrast was stark: on the KOSPI and KOSPI 200 futures, both foreign and institutional investors were net sellers, while on the KOSDAQ only foreign investors sold, with retail and institutions buying — a clear divergence in fund flows across markets.

Shifting foreign investor positioning lies at the heart of the volatility. On July 31, foreign investors bought a record net ₩7.2 trillion (approximately $5.0 billion) of KOSPI stocks — the largest single-day foreign net purchase in history — powering the index’s historic rebound after three straight days of losses. But within a day, foreign investors flipped to being the biggest net sellers, adding to market confusion. Retail investors moved in the opposite direction. On July 31, when the KOSPI posted its record gain, retail investors sold a net ₩8.25 trillion (approximately $5.8 billion) — the largest retail net sell on record — using the rebound as a profit-taking opportunity. That contrasts sharply with Aug. 3, when retail investors returned to net buying of ₩2.49 trillion (approximately $1.7 billion) just three days later.

South Korea’s Financial Services Commission (FSC) sharply raised the barrier for retail investors to enter single-stock leveraged ETFs starting July 31. The minimum margin requirement was increased from ₩10 million (approximately $6,995) in combined stocks and cash to ₩30 million (approximately $20,984) in cash only. Since the new rule took effect, average daily trading volume in major single-stock leveraged ETFs has roughly halved, and their market capitalizations have shrunk, according to industry reports. The regulator said the measure was designed to curb the amplifying effect of daily rebalancing trades in leveraged ETFs on Samsung Electronics and SK Hynix share-price volatility.

Experts advise caution in assessing whether the KOSPI’s surge is a short-term overheating phenomenon or a signal of a trend reversal. Despite the record single-day gain on July 31, the index remains more than 20% lower on a monthly basis. For the one-day spike to translate into a sustained uptrend, sustained foreign net buying and continued positive semiconductor industry outlook will be key, analysts say.

Meanwhile, industry observers note that while a premium dislocation — unlike a tracking error — does not trigger delisting requirements even if it persists for an extended period, the fact that ETF prices have diverged from underlying values warrants investor caution.