United Microelectronics (UMC) experienced a pre-market plunge of 5.63%, as the stock came under significant selling pressure ahead of its upcoming quarterly earnings report.

Market expectations point to subdued financial performance, with consensus estimates projecting only modest revenue growth and a substantial year-over-year decline in adjusted earnings per share. Additionally, the company's first-quarter capacity utilization guidance has fallen below the industry average, raising concerns about near-term profitability.

Earlier market optimism about UMC potentially entering the 2D NAND foundry business has been tempered by supply chain analysis highlighting significant challenges in talent acquisition, technology and process integration capabilities, and equipment readiness. The weakness appears to be company-specific as other major semiconductor stocks showed gains during the same trading session.