Seoul — August 28, 2026. Published after the market close. Index figures are official closing values; the currency figure is an as-of reading taken around the close; individual stock and sector figures are intraday readings unless otherwise noted.
The 30-second version
- The KOSPI fell 1.79% to 6,788.88, giving back the prior session’s 1.53% bounce, as AI chip heavyweights faced profit-taking after Nvidia’s earnings.
- The KOSDAQ eked out a 0.09% gain to 838.41 — strength in individual growth names offset large-cap weakness.
- Morning flow data showed retail investors buying while foreigners and institutions sold on both boards (final exchange figures may differ).
- Samsung Biologics was the worst large cap, down 6-7% in intraday readings; pharmaceuticals was the weakest sector at -3.75%.
- The won strengthened about 0.8% to around 1,372 per dollar.
- The day’s real event was still ahead at the close: new Fed Chair Kevin Warsh’s first Jackson Hole speech at 11 p.m. Seoul time.
Chips gave back the prior session’s bounce
The KOSPI dropped 123.49 points to close at 6,788.88, a 1.79% decline that reversed the prior session’s 1.53% rebound. The story was concentrated at the top of the index: after Nvidia’s earnings in the US, profit-taking hit Korea’s AI semiconductor complex and foreign money pulled back. Digital Daily reported foreign and institutional selling pressing the index lower from the open.
Samsung Electronics was quoted at 260,500 won (about $190 at today’s rate) in intraday readings, down 1.9-2.1%. SK hynix was quoted at 1,705,000 won (roughly $1,240), down 1.5-2.2% per the same readings. These are intraday figures, not confirmed closes — official closing prices for individual stocks were not verified by press time and may differ. The steepest large-cap fall belonged to Samsung Biologics, down 6.09-7.03% in intraday reports, which dragged the pharmaceutical sector to a 3.75% loss — the day’s worst. Utilities (-2.83%) and general services (-1.77%) also lagged.
Breadth was poor: a morning count showed 546 KOSPI decliners against just 285 advancers. The green spots were narrow — IT services (+1.80%) and chemicals (+1.79%) at the sector level, and among large caps, component maker Samsung Electro-Mechanics (+2.38%) and Hyundai Motor (+1.01%). Market commentary has pointed to money rotating out of crowded chip giants into biotech and robotics small caps in recent weeks, though that is a background trend rather than a confirmed single-day list; today’s verifiable gainers were limited to the two names above.
Retail bought the dip; foreigners and institutions sold
A caveat first: the investor-flow figures below come from press reports taken around 9:00-9:30 a.m., so the final Korea Exchange (KRX) totals may differ in size — the direction, however, is reliable.
On the KOSPI, individual investors were net buyers of roughly 65.3-94.7 billion won (about $48-69 million at the day’s exchange rate), while foreigners sold a net 23.6-80.9 billion won and institutions sold a net 81.9-114.8 billion won (up to about $84 million). Program trading — large basket orders driven by algorithms, often tied to index arbitrage — added a further 68.6 billion won of net selling.
The KOSDAQ saw the same tug-of-war in miniature: individuals bought around 68.8 billion won net, against roughly 57.8 billion won of foreign selling and 11 billion won of institutional selling. Yet the junior index closed marginally higher. The difference is composition: the KOSDAQ is far less dominated by the chip giants that bore the brunt of today’s selling, so gains in individual growth names were enough to hold the line.
The real event starts at 11 p.m. Seoul time
Much of today’s caution was anticipatory. Kevin Warsh, the newly installed Federal Reserve Chair, delivers his first Jackson Hole speech since taking office at 11 p.m. Korea time tonight — hours after the Seoul close. With US July PCE inflation coming in at 3.7%, the market’s focus is on how Warsh proposes to handle stubbornly high inflation, and local commentary expects currency and equity volatility to swing on the outcome. Because the speech lands overnight for Korea, it is the single biggest variable for the open of the next Korean trading session.
The won, meanwhile, strengthened about 0.8% to around 1,372 per dollar amid broad dollar softness — one of the few risk-friendly signals on an otherwise defensive day.
Key numbers
| Item | Level | Change | Note |
|---|---|---|---|
| KOSPI | 6,788.88 | -1.79% (-123.49 pts) | Confirmed close; previous close 6,912.37 |
| KOSDAQ | 838.41 | +0.09% | Confirmed close; marginally higher |
| USD/KRW | around 1,372 | down about 0.8% | As-of reading near the close; won stronger |
| Samsung Electronics | 260,500 won | -1.9% to -2.1% | Intraday reading; official close may differ |
| SK hynix | 1,705,000 won | -1.5% to -2.2% | Intraday reading; official close may differ |
What to watch next
- The tone of Fed Chair Warsh’s Jackson Hole speech (11 p.m. Seoul time tonight) — the key driver for the open of the next Korean trading session.
- Final KRX-confirmed investor flow data and closing prices for today, which will replace the morning and intraday estimates cited above.
- Whether foreign selling in Samsung Electronics and SK hynix extends into a trend or proves to be one-day post-Nvidia profit-taking.
- Whether the reported rotation into biotech and robotics small caps continues to cushion the KOSDAQ.
FAQ
Why did the KOSPI fall on August 28, 2026?
Two forces combined: profit-taking in AI chip heavyweights such as Samsung Electronics and SK hynix following Nvidia’s earnings, and wait-and-see de-risking ahead of new Fed Chair Kevin Warsh’s Jackson Hole speech. Foreigners and institutions were net sellers in morning readings, and 546 stocks fell against 285 gainers.
Why did the KOSDAQ rise while the KOSPI fell?
The KOSDAQ closed up 0.09% at 838.41 because it carries much less weight in the semiconductor giants that led the decline. Retail buying in individual growth names was enough to offset the same foreign and institutional selling pattern seen on the main board.
What time is the Jackson Hole speech for Korean markets?
Kevin Warsh speaks at 11 p.m. Korea time on August 28 — after the Seoul close. Any market reaction will show up first in overnight currency moves and then in the open of the next Korean trading session.
Did foreign investors sell Korean stocks today?
Yes, per morning intraday readings: a net 23.6-80.9 billion won of selling on the KOSPI and roughly 57.8 billion won on the KOSDAQ. Final confirmed KRX figures may differ in magnitude, though the direction is reliable.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.
Related reading
Also on Seoul Closing Bell
A companion piece on the same session, written from a different angle: Why KOSDAQ Stayed Green as KOSPI Dropped 1.79%.