United Microelectronics (UMC) stock surged 9.89% in pre-market trading, extending gains from the previous session.

The sharp rise reflects a broader rally in semiconductor stocks, driven by strong signals from key industry players about sustained artificial intelligence (AI) demand. Taiwan Semiconductor Manufacturing (TSMC), the world's leading chipmaker, reported net profit jumped approximately 58% year-over-year, citing robust demand for AI chips, and raised its revenue outlook for 2026. Additionally, ASML, a critical supplier of advanced chipmaking equipment, posted strong first-quarter results and raised its 2026 outlook, indicating that chipmakers are placing heavy orders to keep up with rising AI demand.

These positive developments from major semiconductor industry leaders have created bullish sentiment across the entire sector, benefiting companies like United Microelectronics.