Ideaya Biosciences is trading 4.12% down at $38.08 as U.S. equities weaken amid higher oil prices and Treasury yields. - The Nasdaq Composite is down 1.04%, while biotech ETF XBI is rising during regular trading; the decline appears macro-driven rather than sector-led. - No clear company-specific announcement dated September 23, 2026 has emerged. Latest identified company news was the September 9 OptimUM-11 Phase 3 dosing announcement. Confidence is medium because company-specific coverage is limited.