UMC is trading 8.17% down at $25.47 following a sharp pullback from its previous close of $27.73. The decline comes as investors are pocketing gains built in recent sessions from a reported partnership with Intel Corp. on 3-nanometer development. The move aligns with a broader market downturn in technology and semiconductor stocks, driven by AI-cost concerns and a rotation out of growth stocks, with the Nasdaq Composite falling 0.91% during the session.