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

UMC surged 15.75% in after-hours trading following robust December 2025 revenue of NT$19.28 billion (a 1.7% year-on-year increase) and a strategic partnership with Microchip Technology’s SST subsidiary to launch the 28nm SuperFlash Gen 4 Automotive Grade 1 Platform. The collaboration, highlighting advancements in automotive controller technology, reinforced investor confidence alongside UMC’s full-year 2025 revenue growth of 2.3% to NT$237.55 billion. Strong financial performance, including a 9.6% stock price rise to $8.90 during the session, underscored market optimism about UMC’s market positioning and innovation capabilities.