Seoul — August 25, 2026. Published after the market close; prices are official closing values.
The 30-second version
- The KOSPI opened down 2.40% and fell as much as 4.30% intraday to 6,408.82 after an overnight rout in US chip stocks — then reversed hard to close up 0.68% at 6,742.74, a swing of roughly 5 percentage points off the low.
- The KOSDAQ briefly slipped below the 800 mark before rebounding to finish up 1.70% at 827.15, led by battery names.
- Samsung Electronics and SK Hynix clawed back most of their morning losses and drove the turnaround; the KRX AI Semiconductor theme index rose 2.14%, second-best among 39 theme indices.
- An afternoon snapshot — taken before the final leg of the rebound — showed foreign investors net sellers of about 3.13 trillion won (roughly $2.3 billion) on the main board, with retail and institutional money buying the dip. Final closing flows may differ.
- Nvidia reports second-quarter earnings on Wednesday, August 26 (US time) — the week’s biggest known risk event for Korean chip stocks.
A 4% plunge, gone by the close
Tuesday’s session was really two sessions. The first followed the script written overnight in New York, where Nvidia fell 2.91% for a seventh straight losing day — its longest streak since September 2022 — while Micron dropped 5.83% and Broadcom 2.63%. Warnings about potential AI-related regulation were cited as a backdrop to the broader US tech selloff. Korean traders arrived to that news, and the KOSPI gapped down 2.40% at the open before sliding to 6,408.82, off 4.30%.
The second session began in the afternoon. Samsung Electronics and SK Hynix — the two heavyweight chipmakers that dominate the index — recovered most of their losses, and the KOSPI turned positive, ultimately closing up 0.68%. In other words, Korean chip stocks refused to follow their American counterparts down, and because those two names carry so much index weight, their recovery lifted the whole market with them. Notably, the won barely moved: USD/KRW finished around 1,386 per dollar, little changed — hardly the currency behavior of a market in genuine panic.
Who sold, who bought
A caveat up front: confirmed end-of-day flow data was not available at publication, so the figures below come from an afternoon snapshot taken before the final stretch of the rebound. Treat them as directional, not definitive.
As of that snapshot, foreign investors had net sold about 3.13 trillion won (~$2.3 billion) of main-board (KOSPI) stocks, while individual investors net bought about 1.01 trillion won (~$730 million) and institutions about 725 billion won (~$520 million). Retail bargain-hunting during the morning plunge appears to have helped narrow the losses. Trading was heavy: roughly 235 million shares changed hands for about 18.8 trillion won (~$13.6 billion) in turnover.
One open question: since the index kept climbing after this snapshot was taken, foreign selling may have shrunk by the close. The confirmed figures, once published, will tell us whether foreigners actually capitulated or merely paused.
The rotation: batteries and bio carry the KOSDAQ
Beneath the index drama, money kept rotating. On the KOSDAQ, battery-sector heavyweights led the charge: EcoPro BM jumped 9.09% to 115,200 won and EcoPro gained 6.00% to 86,600 won, extending a rotation into large-cap battery names. Biotech added support, with PharmaResearch up 3.25%, LigaChem Bio up 3.40%, and Peptron up 2.41%.
The flip side of rotation is that someone gets left behind. SK Square fell 3.07% and LG Energy Solution lost 3.18% (per the afternoon snapshot; final figures may vary), while robotics names and some large-cap tech stocks lagged as funds concentrated in semiconductors and batteries.
Also still in the background: Samsung Electronics’ board has approved a record shareholder-return program of 90 to 110 trillion won (roughly $65-79 billion), and the market continues to parse the execution details — the timing of buybacks and share cancellations — for direction on the stock.
Key closing numbers
| Item | Close | Change |
|---|---|---|
| KOSPI | 6,742.74 | +0.68% |
| KOSDAQ | 827.15 | +1.70% |
| USD/KRW | Around 1,386 | Little changed |
| KOSPI intraday low | 6,408.82 | -4.30% at the low |
| KRX AI Semiconductor theme index | — | +2.14% |
What to watch next
- Nvidia Q2 earnings, August 26 (US time). Any sign of slowing growth could rattle Korean chip stocks all over again; Tuesday’s rebound raises the stakes.
- Confirmed investor-flow data. Did foreign selling shrink into the close, or did retail and institutions absorb the full 3-trillion-won-plus wave alone?
- Samsung’s shareholder-return mechanics. How and when the buyback and cancellation program is executed remains a live driver for the market’s biggest stock.
- The US tech-versus-everything-else split. Monday’s US session (prior to Seoul’s Tuesday trade) saw the Dow hit a record high, up 0.26%, while the S&P 500 fell 0.28% and the Nasdaq dropped 0.76% — a rotation away from tech that Korea’s chip-heavy indices cannot ignore.
FAQ
Why did the KOSPI fall and then recover on August 25, 2026?
The morning drop tracked an overnight selloff in US semiconductor stocks — Nvidia’s seventh straight decline, plus sharp falls in Micron and Broadcom, amid AI-regulation worries. In the afternoon, Samsung Electronics and SK Hynix recovered most of their losses, and because they dominate the index, the KOSPI swung from -4.30% at its low to +0.68% at the close.
Are foreign investors selling Korean stocks?
They were on Tuesday, at least through mid-afternoon: a snapshot showed about 3.13 trillion won (~$2.3 billion) of net foreign selling on the KOSPI, against net buying by retail and institutions. Because the index rallied further after that snapshot, the confirmed end-of-day figure may show a smaller foreign outflow.
Why do Nvidia’s earnings matter for the Korean stock market?
Samsung Electronics and SK Hynix supply memory chips into the AI hardware ecosystem, and sentiment on Korean semiconductors moves closely with Nvidia. Its Q2 report on August 26 (US time) is this week’s biggest scheduled event; a growth disappointment could reignite the selling that hit Korean chip names on Tuesday morning.
What is Samsung Electronics’ shareholder return plan?
Samsung’s board has approved a record shareholder-return program worth 90 to 110 trillion won (about $65-79 billion). The market is now focused on execution — the timing of share buybacks and cancellations — which continues to influence the stock’s direction.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.
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Also on Seoul Closing Bell
A companion piece on the same session, written from a different angle: Samsung and SK Hynix Shrugged Off Nvidia's Seven-Day Slide.