Seoul — August 04, 2026. Midday update, published before the 3:30 p.m. close. August 4 figures are an intraday snapshot, not official closing values; August 3 figures are confirmed official closes.
Data note: At publication time, the official August 4 closing prints had not yet been released by the exchange data feeds we track. Today’s figures below are an intraday snapshot taken around 11:20 a.m. Seoul time; August 3 numbers are confirmed official closes. We flag which is which throughout, and a full closing-bell update will follow once final August 4 data — index closes, investor flows and individual stock moves — has been confirmed against KRX figures.
The 30-second version
- The KOSPI closed Monday, August 3 at 6,257.45, down 338.00 points or -5.12% — a sharp pullback after its record 17.91% single-day surge on July 31.
- On Tuesday the index opened strong at +1.50% (6,351.38), then swung to roughly -2.7% (low near 6,080) before stabilizing around 6,228 (-0.47%) by late morning.
- The KOSDAQ went the other way: up 4.85% at the late-morning snapshot, triggering a buy-side sidecar for the third straight session — the 30th this year.
- The story underneath: profit-taking in Samsung Electronics and SK Hynix, and a rotation into biotech, robotics and battery names.
A rollercoaster with the volume turned up
Korean equities are in an extreme-volatility stretch that local media have nicknamed the “roller-KOSPI.” On July 31 the index posted its largest one-day gain ever — +17.91%, or 1,001.89 points, to 6,595.45. Monday gave a chunk of that back with a 5.12% drop, and Tuesday’s session — still in progress at our snapshot — was a tug-of-war: a strong open, a slide to the 6,100s, then a grind back toward 6,220-6,230 by late morning. Strategists quoted in local coverage argue July’s original selloff overshot fundamentals and expect an August recovery attempt, but say two things need to hold: buying interest returning to the large-cap chipmakers, and a calmer won (Newspim’s recap of Monday’s 5.12% drop).
The chip trade takes a breather
Monday’s damage was concentrated where the prior rally had been: Samsung Electronics fell 8.76% to 239,500 won and SK Hynix fell 8.79% to 1,567,000 won at Monday’s close. Foreign and institutional investors together sold roughly 4 trillion won of just those two stocks — around 70% of all foreign selling on the KOSPI that day was in those two names. That is classic profit-taking after last week’s surge, amplified by renewed “peak-out” worries about the semiconductor and AI cycle ahead of both companies’ earnings reports this week.
Monday’s official KOSPI flow data shows the scale of the handoff: individuals bought a net 6.43 trillion won, while foreigners sold 3.87 trillion won and institutions sold 2.66 trillion won. By Tuesday’s late-morning provisional numbers the selling had cooled dramatically — individuals +680.3 billion won, foreigners -84.9 billion won, institutions -696.8 billion won on the KOSPI. Both chip giants were back in the green at the snapshot (Samsung +1.25% at 242,500 won, SK Hynix +2.55%), though with violent intraday swings that briefly dragged the whole index down to the 6,100 level — how they finish the afternoon remains to be seen.
KOSDAQ: three sidecars in a row
While the KOSPI wobbled, the small-cap-heavy KOSDAQ surged — up 4.85% at the late-morning snapshot after closing Monday up 2.44% at 737.35, snapping a six-session losing streak. The rally was strong enough to trigger a buy-side sidecar for a third consecutive session (July 31, August 3, August 4). A sidecar is a Korean market circuit-breaker-lite: when index futures move sharply, program-trading orders are paused for five minutes to let the market catch its breath — think of it as a speed bump rather than a full road closure. This was the 30th sidecar of 2026, which itself tells you how unusual this stretch is.
The fuel was rotation plus a tailwind from New York, where Microsoft (+4.93%) and Meta (+6.02%) jumped on renewed optimism about AI investment payoffs. In Seoul, that translated into morning buying of biotech (ABL Bio +8.03%, Alteogen +6.46%, HLB +5.02%), batteries (EcoPro +5.43%, EcoPro BM +4.96%) and chip-equipment names (Jusung Engineering +4.38%, Wonik IPS +3.31%), with multiple KOSDAQ stocks hitting the 29-30% daily limit-up. Notably, institutions were net buyers of the KOSDAQ (+363.3 billion won) even as they sold the KOSPI — a clean picture of money rotating rather than leaving (Financial News morning wrap).
Key numbers
| Aug 3 official close | Aug 4 intraday snapshot (~11:18 KST) | |
|---|---|---|
| KOSPI | 6,257.45 (-5.12%) | 6,228.21 (-0.47%); ranged +1.77% to about -2.7% |
| KOSDAQ | 737.35 (+2.44%) | 773.13 (+4.85%); intraday high near +5.87% |
| USD/KRW | 1,429.8 (+5.8 won) | Opened 1,443.10; traded 1,419.01-1,448.11 |
| Samsung Electronics | 239,500 won (-8.76%) | 242,500 won (+1.25%) |
| SK Hynix | 1,567,000 won (-8.79%) | +2.55%, with heavy intraday swings |
What to watch next
- Today’s close — final August 4 index levels, investor flows and stock moves need confirming against KRX data after 3:30 p.m.; we will publish a closing update once they are.
- Samsung Electronics and SK Hynix earnings this week — the direct test of the “AI peak-out” worry that drove Monday’s selloff.
- The won: USD/KRW is swinging in a wide 1,420-1,450 band, and a weaker won tends to discourage foreign buying of Korean stocks.
- Fed aftershocks: the July FOMC left lingering debate about tariff-driven inflation, keeping rate-path uncertainty alive.
- Structural noise: analysts flag leveraged-ETF flows distorting index moves, and lingering worry about yen carry-trade unwinds. Retail investors’ share of trading has fallen from 48% to 31% in half a year — a shift in who sets prices.
FAQ
Why did the KOSPI fall 5% on August 3?
Mostly profit-taking in two stocks. After a record 17.91% surge on July 31, foreign and institutional investors sold roughly 4 trillion won of Samsung Electronics and SK Hynix combined, and both fell nearly 9%. Because those two carry enormous index weight, the KOSPI dropped 338 points.
What is a sidecar in the Korean stock market?
A sidecar is an automatic five-minute pause on program-trading orders, triggered when index futures move sharply. It is milder than a full circuit breaker — a speed bump designed to slow momentum-driven order flow. The KOSDAQ triggered buy-side sidecars three sessions running, the 30th of 2026.
Why is the KOSDAQ rising while the KOSPI struggles?
Rotation. Money leaving large-cap semiconductors moved into KOSDAQ biotech, robotics and battery names, helped by a strong AI-driven session for US big tech. Institutions were net buyers of the KOSDAQ on Tuesday morning even while selling the KOSPI.
Is today’s data final?
No. The August 4 figures here are an intraday snapshot from about 11:20 a.m. Seoul time, taken before the 3:30 p.m. close. August 3 figures are official closing values. Final August 4 numbers should be confirmed against KRX data after the close, and we will follow up with a closing-bell update once they are available.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.