SEOUL, July 28, 2026, 17:12 KST — Trading ended for the day.
- The KOSPI dropped 10.84% to close at 6,023.66, marking its steepest one-day loss since March 4.
- Shares of SK Hynix dropped 14.7%, while Samsung declined 13.4%.
- Foreign investors offloaded 5 trillion won, as retail investors bought 4 trillion.
South Korea’s main index slumped on Tuesday, weighed by a sharp sell-off in chipmakers. SK Hynix KRX:000660 plunged 14.7% as Samsung Electronics KRX:005930 fell 13.4%.
Investor concern was focused more on concentration than just panic. The two major chipmakers account for over half of KOSPI’s total market weight. Taking Samsung’s lesser drop sets a conservative baseline for their combined effect. Based on a straightforward calculation of weighting and returns, the duo contributed a minimum of 6.7 percentage points. This represents approximately 62% of the index’s overall decline.
However, losses were widespread across the board. Out of 917 shares traded, 878 fell while just 36 gained. Declining stocks made up 95.7% of the market.
| Asset | Tuesday move | Investor signal |
|---|---|---|
| KOSPI | -10.84% to 6,023.66 | Sharpest drop since March 4; circuit breaker initiated |
| SK Hynix | -14.7% | U.S. stock ended Monday at $143.02, under the $149 offer price |
| Samsung Electronics | -13.4% | Largest one-day fall in nearly 20 years |
| Kioxia Holdings TYO:285A | -18.3% | Biggest drop among major memory chipmakers in the region |
| Nikkei 225 | -4.0% to 62,364.92 | Selloff spread into Japan’s tech sector |
The KOSPI fell 29% in July after Tuesday’s close. While the index was 34% off its June high, it was still 43% higher in 2026.
Foreign investors recorded net sales of 5 trillion won, equal to $3.42 billion. In contrast, retail investors made net purchases amounting to 4 trillion won. As a result, domestic investors ended up shouldering increased near-term market exposure.
Leverage intensified the shift. Regulators have indicated they could limit retail access to single-stock leveraged ETFs. Imposing restrictions may prompt additional position reductions ahead of a return to calmer conditions.
China introduced a second trigger. ChangXin Memory Technologies SHA:688825 secured $8.6 billion in Shanghai on Monday. The company’s shares surged 466% before falling roughly 4% on Tuesday.
Investors responded to news regarding Chinese immersion-DUV manufacturing. Competing equipment may speed up increases in memory capacity. Still, details on performance and timelines for commercial launch have not been provided.
Analyst Kim Seok-hwan from Mirae Asset noted that investors were concerned about prospective capacity rather than present earnings. Cameron Systermans at Mercer, however, provided a differing perspective, stating that CXMT is still several years behind their Korean competitors in the area of high-bandwidth memory.
Wall Street’s performance pulled down Asia’s opening levels. Nvidia NASDAQ:NVDA slid 5% on Monday. Advanced Micro Devices NASDAQ:AMD retreated 5.2%. Micron Technology NASDAQ:MU declined 2.3%.
The Wall Street Journal reported that Nvidia might provide up to $250 billion in guarantees for OpenAI. According to Reuters, the deal is still being negotiated and has not yet been finalized. The news intensified worries that chip demand is becoming more tied to financing offered by suppliers.
Scheduled supply is another key factor. According to the Financial Times, Samsung and SK Hynix have outlined four planned Korean semiconductor plants. Their collective investment over five years reaches roughly 800 trillion won, or $548 billion. The initiative targets a twofold increase in DRAM output.
As earnings take center stage over macro headlines, SK Hynix is set to release results on Wednesday ahead of 9:00 a.m. KST, with its conference call beginning at 9:00 a.m. Samsung will publish its full results Thursday at 10:00 a.m. KST.
Investors are set to gauge appetite for HBM, assess DRAM price trends, and monitor capacity strategies. In the first quarter, SK Hynix accounted for 58% of HBM revenue, while Samsung and Micron each secured 21%. This dominance bolsters margins, but also increases risk if AI-driven demand shifts.
Markets have entered “the despair part of the selloff,” according to StoneX analyst Matt Simpson. Opinions are divided; Morningstar’s Jing Jie Yu described Tuesday’s trading as “largely a knee-jerk reaction and overdone.” Reuters
The primary threat to a recovery is the potential for another forced sell-off if guidance remains weak. Chinese equipment updates also do not provide clear information on performance or commercialisation schedules. However, an upbeat HBM forecast might swiftly shift the trade direction.
The tone on Tuesday was direct. South Korea continues to handle AI risk at the company level using a single national benchmark. Now, earnings results will show whether the market overreacted when adjusting for that risk.
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