KOSPI · June 23, 2026

The day doubt about AI broke out

-9.99%

single-day change vs previous close

Part of a longer stretch

The AI bubble argument hits the KOSPI

early in it · 2026-06-22 → 2026-07-30, -38.63% over the whole period

What happened that day?

The KOSPI fell 9.99% on the day. The decline that began here became the largest monthly drop in KOSPI history
It started with a US chip company lowering its revenue forecast in early June, and doubt spread about whether spending on artificial intelligence would continue
The character of this fall is that earnings had not worsened — prices had run ahead. What was cut was the multiple attached to the profits, not the profits
Money had been crowding into Samsung Electronics and SK Hynix since the start of 2026. A position everyone is on one side of unwinds all at once
Those two carry enough weight in the KOSPI that a story about the chip cycle becomes a story about the index
The decline ran to 30 July

Sources

Every figure on this page is recomputed from the original daily closing prices and checked against them at build time. The account of what happened is written from the sources listed above.