Keyword → KOSPI circuit breaker

SK Hynix Falls 15.4% in Record Seoul Plunge — KOSPI Triggers 7th Circuit Breaker of 2026 as AI Memory Unwind Spreads to US Premarket

SK Hynix shares fell 15.4% in Seoul — their worst single-session decline on record — dragging the KOSPI down 8.95% and triggering a 20-minute market-wide circuit breaker, the seventh of 2026. The rout came just one day after SK Hynix's $26.5 billion US ADR debut, as arbitrage selling, a downgraded Q2 profit forecast from Korea Investment & Securities, and renewed US-Iran tensions converged. Micron Technology and the VanEck Semiconductor ETF are both lower in US premarket trading.

OpenAI Weighs IPO Delay to 2027 at $1 Trillion Valuation — SoftBank Plunges 13%, KOSPI Triggers Circuit Breaker as Nasdaq 100 Futures Slide 0.9%

The New York Times reported that OpenAI is considering delaying its initial public offering until 2027, targeting a $1 trillion valuation rather than accepting a lower figure in choppy markets. The news sent SoftBank Group plunging 13%, wiping out 5.6 trillion yen in market value, and triggered an 8% collapse in South Korea's KOSPI that activated a circuit breaker. Nasdaq 100 futures fell 0.9% as investors broadly reassessed AI-sector valuations heading into a pivotal quarter-end Friday.