South Korea's KOSPI index plummeted 9% on Friday, triggering a trading halt for the second time in a week, as semiconductor giants Samsung Electronics and SK Hynix each shed more than 10% amid a sharp reversal in investor sentiment. Foreign investors pulled approximately $3.2 billion (5 trillion won) from Korean equities in a single session, according to Bloomberg.
The dramatic reversal followed Thursday's rally, when optimism had been fueled by Micron Technology's bullish chip-memory guidance and SK Hynix's planned U.S. listing announcement. Friday's selloff reflected growing concerns that artificial-intelligence enthusiasm had overheated, coupled with uncertainty around OpenAI's delayed initial public offering and weakening demand for Apple devices due to memory-chip constraints and rising prices.
The volatility has been amplified by structural factors unique to Korea's market: retail investors heavily trade on margin, while leveraged exchange-traded funds on chipmakers magnify price swings. Samsung and SK Hynix together constitute nearly 60% of the KOSPI's index weight, concentrating the damage.
The implications for cryptocurrency markets are material. Korea hosts one of the world's most active retail crypto trading ecosystems, particularly in altcoins. When Korean retail positions in equities—especially margin-backed holdings—deteriorate sharply, a portion of that investor base typically de-risks by closing leveraged crypto positions and rotating into cash, creating downstream selling pressure on digital assets.