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Limited seats available, first come first served. Let us journey together toward a sustainable future! [Click to register] Today (October 15, 2026), the South Korean stock market experienced a historically brutal day. Hit by a "double blow" of unexpectedly strong US inflation data and the accelerating collapse of global AI chip valuation bubbles, pessimistic sentiment on the Seoul bourse was instantly ignited. The Korea Composite Stock Price Index (KOSPI) plunged 7.57% at close (down 455.51 points), finally settling at 5,554.22 points. This crash not only wiped out months of bullish gains in one fell swoop, but also marked the lowest closing level since April 7. With this, the KOSPI has now fallen for a seventh consecutive trading session, sinking into a rare deep bear market pattern.

The two chip giants bore the brunt of the selling

As the absolute cornerstone of the South Korean stock market, the semiconductor sector became the hardest-hit area of indiscriminate capital dumping today. Since the two leading companies account for an extremely high proportion of the KOSPI's total market capitalization, their collapse dragged the broader index into an abyss. At today's close, the stock performance of the two chip giants was extremely brutal: Samsung Electronics: plunged 9.48% at close, with shares falling to 210,000 Korean won. SK Hynix: plummeted 10.01% at close, finally settling at 1,277,000 Korean won.

Multiple bearish factors resonate in the market

US inflation ignites the high interest rate fuse: The US September Consumer Price Index (CPI) released overnight unexpectedly rose, completely shattering global investors' hopes for a near-term aggressive rate cut by the Federal Reserve. Elevated borrowing costs directly suppressed the premium space for high-valuation assets such as tech stocks. The AI industry's growth myth faces comprehensive scrutiny: The market has recently not only questioned the monetization capacity of tech giants' massive capital expenditures, but also the rapid technological catch-up by Chinese memory chip manufacturers (such as CXMT), which has triggered foreign investors' long-term concerns about South Korea's traditional memory monopoly position. Capital stampede and long liquidation: According to foreign wire analysis, some highly leveraged hedge funds' positions in South Korean memory chips were forced into cascading liquidations today, compounded by the stampede of double single-stock leveraged ETF longs favored by retail investors, causing intraday selling pressure to be mechanically amplified multiple times over.

The KOSPI plunged as much as 8% during intraday trading, triggering a market circuit breaker. This was the tenth circuit breaker triggered in the South Korean stock market this year. The Korea Exchange announced on the same day that starting from 12:38 PM local time on the 15th, KOSPI trading would be suspended for 20 minutes. As a result, all stock trading on South Korea's securities market was temporarily halted, and related futures and options market trading was also simultaneously suspended. When the circuit breaker was activated, the KOSPI stood at 5,528.05 points, down 480.76 points from the previous trading day, a decline of 8%. Yonhap News Agency reported that controversy over AI investment returns is heating up, with South Korean semiconductor stocks leading the decline. Analysts believe that recent financing bottlenecks facing AI infrastructure investment, combined with the continued weakness of US tech stocks and semiconductor stocks, have dealt a blow to South Korea's semiconductor sector. The KOSDAQ index, known as South Korea's version of the Nasdaq, also fell sharply on the same day and similarly triggered a market circuit breaker.

Market outlook

Today, the KOSPI index at one point triggered high-frequency trading restrictions or program trading suspensions due to excessive declines. Since global AI frenzy pushed the KOSPI to a historic peak above 9,000 points in June this year, the index has retraced more than 35% from its high in just a few months. In the short term, South Korea—as a sensitive "barometer" of the global AI hardware chain—has been the first to bear the pain of valuation deleveraging. As foreign capital outflows from the Seoul market accelerate significantly and the Korean won has fallen to its lowest level since the 2008 financial crisis, the market may continue to experience violent fluctuations at the bottom in the short term, absent strong policy support or clear signals of a halt in the decline of US tech stocks.