Kospi posts worst quarterly performance globally, down 18.8% on Samsung and SK Hynix sell-offs

South Korea's Kospi fell 18.8% in Q3 2026, the worst performance among major global stock markets, driven by a July sell-off in Samsung and SK Hynix shares. The index is still up 60% year to date.

• Kospi dropped 18.8% in Q3, the worst globally
• Sell-offs in Samsung and SK Hynix began in July
• Index remains up 60% year to date