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South Korea’s KOSPI tumbles on June 5, triggering circuit breaker as chip stocks slide

South Korea’s KOSPI tumbles on June 5, triggering circuit breaker as chip stocks slide

Asia-Pacific and emerging-market equities fell for a third session, with South Korea’s KOSPI dropping as much as 7% intraday as semiconductor shares slid after Broadcom’s AI outlook disappointed investors.

Fact Check
Multiple independent sources corroborate each element. Chosun confirms the June 5 KOSPI circuit breaker, Samsung -5.55%, SK Hynix -6.96%. BlockBeats confirms KOSPI's intraday decline expanded beyond 6% and Nikkei declines on both June 4 and June 5. SoftBank's 9% drop on June 4 is documented. Odaily corroborates June 5 opening declines.
Summary

Asia-Pacific and broader emerging-market equities weakened across June 4-5, with losses intensifying in South Korea on June 5 as semiconductor stocks sold off. South Korea’s KOSPI opened down 372.6 points, or 4.31%, at 8,266.81, later fell more than 5% to trigger an intraday circuit breaker, and was reported down over 5.5%, over 6%, and as much as 7% intraday in subsequent updates. The MSCI Emerging Markets Index fell 1.7% to 1,728.66 in a third straight day of declines. Japan’s Nikkei 225 also dropped sharply, while China’s ChiNext Index fell more than 3% and Shanghai slipped about 0.7%. Samsung Electronics, SK Hynix and SoftBank were among notable decliners. Reports linked the selloff to weaker-than-expected AI guidance from Broadcom and a circulating research note about Nvidia Rubin memory cuts.

Terms & Concepts
  • KOSPI: South Korea’s main stock market index.
  • Circuit breaker: A market mechanism that temporarily halts trading after sharp price moves to curb panic selling.
  • MSCI Emerging Markets Index: A widely followed benchmark tracking large- and mid-cap stocks across emerging-market economies.