The KOSPI opened more than 1% higher and touched 6,415 before closing down 0.60% at 6,258.77 as foreign investors turned sellers. Battery, defense and bank stocks rallied in intraday trading while semiconductors stayed weak ahead of US July payrolls.
Standard monthly KOSPI 200 options expire on the second Thursday of each month and settle against the 15:20-15:30 closing auction, so some hedge- and arbitrage-linked program flows concentrate into those final ten minutes. Here is how to read the futures basis and KRX program-trade balance beforehand — and what those indicators can and cannot tell you — with a worked reading of August 2026 foreign-flow data.
Korea’s KOSPI fell 4.58% as Samsung Electronics and SK hynix tracked the Nasdaq’s AI-spending scare, triggering a sell-side sidecar. KOSDAQ closed higher on a biotech rotation, and retail investors bought the dip against heavy foreign selling.
Korea’s KOSPI closed at 6,598.26, up 3.76%, after AI semiconductor euphoria from Wall Street triggered a buy-side sidecar and produced 12 limit-up stocks — the most in a day since tracking began in June 2022. Foreigners bought over 1.4 trillion won intraday while retail investors sold.
A day after a 5.12% plunge, the KOSPI swung from +1.8% to -2.7% intraday before stabilizing near 6,228 by late morning, as Samsung Electronics and SK Hynix steadied. The KOSDAQ was up nearly 5% by late morning, triggering its third consecutive buy-side sidecar as money rotated into biotech, robotics and batteries. Figures for August 4 are an intraday snapshot, not final closes.
Korea imports roughly 95% of its energy, so an oil spike widens the trade deficit, pressures the won (which closed at 1,423.98 per dollar on August 4, 2026), feeds inflation, and triggers foreign selling on the KOSPI. Here is the full transmission chain, the sectors hit in each direction, and the exact data releases to watch.
The KOSPI fell 5.12% to 6,257.45 as traders booked profits from Friday’s record 17.91% surge, with Samsung Electronics and SK hynix both down almost 9%. The KOSDAQ climbed 2.44% and triggered a buy sidecar as money rotated into bio and robotics names.
DRAM spot prices historically turn one to two quarters before Samsung Electronics and SK Hynix earnings inflect — and those two stocks drive the KOSPI. Here is where to find the DXI index, DRAMeXchange spot quotes, and hyperscaler capex guidance, and how to read a cycle turn step by step.
The KOSPI surged 17.91% to 6,595.45 — its biggest one-day gain on record — as strong US tech earnings eased AI profitability fears and foreign investors piled back in after a brutal two-week selloff capped by back-to-back circuit breakers.
The KOSPI fell 1.23% to 5,593.56 for a third straight loss as a morning push toward 6,000 collapsed under semiconductor profit-taking. SK hynix sank 5.6% while batteries and banks rallied, and foreign investors returned as net buyers on the main board.