KOSPI plunges 8.4%, circuit breaker halts Seoul trading

Seoul’s KOSPI plunged 8.4% to 7,477 on Monday and triggered a 20-minute trading halt after Samsung Electronics and SK Hynix fell about 10% in a US-led semiconductor selloff. The KOSDAQ index dropped more than 7%.

The decline came shortly after the market opened and was large enough to trip an automatic circuit breaker that paused trading for 20 minutes. Samsung Electronics and SK Hynix are among the largest components of the KOSPI, and their intraday losses amplified the benchmark’s fall. Japan’s Nikkei 225 also fell about 3.4%.

The selloff followed a sharp drop on Wall Street on Friday. The Nasdaq Composite fell 4.18% to 25,709.43, its biggest one-day decline since April 2025. A stronger-than-expected US jobs report for May led traders to scale back expectations for Federal Reserve rate cuts this year, and Treasury yields rose.

Higher yields increased concerns about borrowing costs for technology companies investing heavily in artificial intelligence infrastructure, adding pressure on chip and other tech stocks. Escalating tensions in the Middle East also contributed to market unease.

Cryptocurrencies moved differently on Monday. Bitcoin traded near $63,020, up about 2.7% over 24 hours, and Ether rose roughly 6% to around $1,680. Bitcoin remains more than 45% below its October 2025 record above $126,000, and persistent outflows from spot Bitcoin exchange-traded funds have continued to weigh on prices.

Traders and investors will watch coming sessions for signs of stabilization as companies report earnings, new economic data is released and geopolitical developments evolve.