Korean Retail Investors Sold ₩8 Trillion on the Biggest Up Day in KOSPI History

Diverging bar chart of KRX main-session flows on July 31, 2026: foreign investors net bought KRW 7.22 trillion while Korean retail investors net sold KRW 8.25 trillion.

On July 31, 2026 the KOSPI rose 17.91% — its largest one-day gain ever. In the same KRX session Korean retail investors net sold ₩8.25 trillion while foreigners net bought ₩7.22 trillion. What Korean investors were writing while they sold, why SK Hynix stopped at 29.95%, and why naming the cause of this rally is a trap.