Kospi's Second Circuit Breaker Day: Retail Panic-Sells ₩2 Trillion

The Kospi closed down 5.98% at 5,663.24 on Wednesday, triggering a marketwide circuit breaker for the second straight trading day — the first time that has ever happened in the index's history — as Korean retail investors dumped roughly ₩2 trillion worth of stock in a single session.

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What Happened

A sell-side sidecar hit the Kospi around 10:55 a.m. local time, and by 12:32 p.m. the index had fallen far enough to trip a full 20-minute circuit breaker that froze trading on both the Kospi and Kosdaq. At one point in the session the Kospi was down 9.93%, before institutional buying pared the loss to a close of 5.98%. It was the second consecutive day of circuit breakers after Tuesday's 10.84% rout — a sequence I covered in Kospi's Worst Day Ever: 10.84% Crash Shatters the 6,000 Line — and it marks the first back-to-back circuit-breaker stretch in the exchange's history, according to the Korea Economic Daily and Korea JoongAng Daily.

Trading data showed institutions net-bought about ₩3.15 trillion in an apparent attempt to defend the index, while individual investors net-sold roughly ₩1.98 trillion and foreign investors sold another ₩1.22 trillion. Combined market capitalization across both days of selling has now wiped out roughly ₩921 trillion, per Financial News.

Why It Matters

SK Hynix, the epicenter of the selloff, fell about 10% to 1,395,000 won after an intraday drop as steep as 18%. But the more startling number came from derivatives: the single-stock leveraged ETF tracking SK Hynix plunged more than 32% in one day, according to Seoul Economic Daily, as daily-reset leverage amplified the underlying stock's swings in both directions. That's the exact mechanism I broke down in Your Leveraged ETF Can Lose Money Even When the Stock Wins — compounding decay turns a bad day into a brutal one. South Korea's Finance Minister, Gu Yun-cheol, publicly acknowledged regulatory gaps around single-stock leveraged products following the rout, a step beyond the leverage-cap proposal I flagged in Seoul's Regulators Move to Cap Leverage After Chip Crash.

The selling pressure traces back to reports that a Chinese state-backed chipmaker has begun producing domestic immersion DUV lithography equipment, deepening fears that Korean and Western chipmakers' technology lead over Chinese rivals is shrinking faster than expected.

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Who's Affected

• Samsung Electronics and SK Hynix — both stocks led the two-day rout, with Samsung also sliding double digits intraday alongside SK Hynix.
• Single-stock leveraged ETF holders — retail traders in SK Hynix and Samsung 2x products are sitting on losses far steeper than the underlying stocks, and some are now below half their listing price, per Seoul Economic Daily.
• U.S. chipmakers — the contagion crossed the Pacific before the U.S. open. Micron fell more than 6% in premarket trading Wednesday, while Nvidia slipped about 1.1%, extending Tuesday's premarket declines that also dragged down AMD and Intel, according to Benzinga and TradingKey.

What to Watch Next

The Federal Reserve's rate decision landed the same afternoon as this second circuit breaker, with the FOMC holding its target range steady at 3.50%–3.75%. Because this meeting carries no fresh Summary of Economic Projections, Jerome Powell's press conference language will be the main signal markets parse for clues on the path ahead — arriving at a moment when Asian chip stocks are already jumpy. Also worth tracking: whether Seoul's Finance Ministry follows its regulatory acknowledgment with concrete leverage caps on single-stock ETFs, and whether U.S. premarket chip weakness carries through to the regular session or gets bought back, as it did after Tuesday's initial shock.

This is not financial advice — always do your own research before making investment decisions.

Two circuit breakers in a row is rare enough that traders on both sides of the Pacific are paying attention, but the mechanics matter as much as the headline: institutional buying is cushioning the index, leveraged retail bets are getting wiped out disproportionately, and the trigger — China's advancing chip capability — isn't a one-day story. Watch the follow-through in Korean chip stocks and their U.S. peers over the next few sessions rather than reacting to any single close.