Black Tuesday, Seoul edition
South Korea’s KOSPI didn’t just wobble — it face-planted, dropping 10% on June 23 and tripping a circuit breaker like the market had yanked the emergency brake. The iShares MSCI South Korea ETF (EWY) felt the pain too, sliding 12.25% in a single session before the mood reversed the next morning.
Why one bad night in chips hit the whole country
The culprit wasn’t some mystery macro gremlin. It was the memory-chip trade getting a sharp reality check. Samsung Electronics and SK Hynix, which together make up roughly half of the KOSPI’s market value, both got smoked when AI and semiconductor stocks sold off on Wall Street ahead of Micron’s earnings. When your index is that concentrated, two bruised giants can drag the whole thing down like an anchor.
Panic first, relief second
Then came the rebound. Samsung jumped more than 9% after reports it was planning a massive share buyback, and SK Hynix was in the spotlight for its own Nasdaq depositary-receipt plan aimed at funding AI-memory expansion. Translation: investors briefly remembered they still like the AI story, just not when it’s wearing a hazmat suit.
What it means for your portfolio
This is the reminder nobody asked for but everybody needed: the AI boom is real, but so is concentration risk. If memory pricing stays hot, Korea’s chip champions can keep printing money. If demand cools or supply catches up, the same names that powered the rally can yank the rug just as fast.
Big picture: the next big mood swing may come from Micron’s results this week, which should tell investors whether the memory supercycle is still humming or starting to sputter.