KOSPI plunges after tech selloff and U.S. rate worries

South Korea's benchmark KOSPI plunged on June 8, 2026, in a technology-led selloff compounded by U.S. interest-rate fears and geopolitical tension. UPI reports the index lost 676.18 points, or 8.29%, to close at 7,484.41, after briefly falling to about 7,442.73. Reuters reports it was the index's biggest daily decline since March 4 and left the KOSPI roughly 15% below its June 2 peak of 8,801.49; the secondary KOSDAQ fell more than 9%, per UPI.

Reporting links the rout to three reinforcing factors: a weaker-than-expected AI-chip revenue outlook in Broadcom's latest results, which soured sentiment toward AI hardware names; stronger-than-expected U.S. payrolls data that revived expectations the Federal Reserve could hold rates higher for longer; and escalating Middle East tensions. Because Samsung Electronics and SK Hynix together account for close to half of the KOSPI's market capitalization, repricing in those names drives outsized index moves.

Reuters reports Samsung Electronics fell about 10% and SK Hynix dropped sharply, with intraday and closing figures varying across outlets. UPI documents heavy losses among major U.S. chip stocks as well, citing declines in Nvidia, Broadcom, and Micron.

UPI reports heavy turnover, with about 448.3 million shares traded worth roughly 47.8 trillion won, and losers far outnumbering gainers. Per UPI, foreigners and institutions were net sellers while retail investors were net buyers. UPI and Reuters report the Korea Exchange activated circuit breakers shortly after the open and applied sell-side sidecars for both the KOSPI and KOSDAQ.

Reuters and Yahoo report the won reversed from a multi-year low after authorities convened emergency meetings and signaled intervention, with market participants expecting officials to sell dollars to cap won weakness; UPI reports verbal intervention.

The session combined a macro tightening scare with rapid profit-taking in AI-exposed semiconductor stocks after an extended rally. For practitioners and investors tracking the AI hardware cycle, concentrated sector exposure plus macro-data surprises raises short-term liquidity and execution risk, and circuit-breaker activations can interrupt strategies that assume continuous market access. Incoming U.S. data, Fed commentary, official FX statements, and chipmaker earnings guidance are the key signals to watch next.