UMC's share price lost momentum today after soaring more than 20% in five sessions — a warning sign for investors who chased the rally, though the fundamentals remain strong.

• UMC climbed from its mid-September low all the way to NT$168.5, a 22% gain over five days, before slipping into negative territory in early trading today to touch NT$158.
• Turnover was heavy but sell orders were also elevated, indicating that some investors have begun taking profits.
• Supporting the share price is AI-driven demand for mature-node processes; August revenue rose 30% year-on-year, marking six straight months of growth.
• Domestic institutional investors bought nearly 60,000 lots in a single week, the largest net purchase in the Taiwan market, and a state-backed securities research firm raised its target price from NT$130 straight to NT$185.
• Foreign institutions are divided: optimists see the stock above NT$230, while the more cautious, worried about overcapacity in mature-node processes in China, put it at just NT$130.

Outlook: In the short term, expect choppy trading at elevated levels as selling pressure emerges; over the medium term, the question is whether AI and advanced packaging orders can sustain the NT$200 mark that institutional investors have flagged.