UMC shares surge 15.75% after hours on December revenue growth and 28nm automotive tech partnership with SST.

UMC surged 15.75% in after-hours trading, driven by robust December 2025 revenue growth of 1.7% year-on-year to NT$19.28 billion and a strategic partnership with Microchip Technology’s SST subsidiary. The collaboration introduced the 28nm SuperFlash Gen 4 Automotive Grade 1 Platform, positioning UMC at the forefront of automotive semiconductor innovation. Full-year 2025 revenue rose 2.3% to NT$237.55 billion, reinforcing investor confidence in the company’s market expansion and financial health. The partnership highlights UMC’s competitive edge in advanced automotive tech, while strong December sales and improved profitability metrics further solidified its appeal. These factors collectively fueled the sharp after-hours rally, reflecting optimism about UMC’s sustained growth trajectory.