UMC shares crashed on Thursday even though its latest quarter beat expectations, because next quarter's profit margin guidance came in weaker than hoped — but analysts still see long-term upside.

• UMC stock fell sharply in early trading, hitting its lowest level in months, as investors took profits after the earnings call.
• Third-quarter results were strong, with record chip shipments and rising factory utilization, but Q4 margin guidance came in below what the market wanted.
• Part of the margin pressure comes from UMC converting some older production lines to make specialized optical chip components, a short-term cost for a longer-term bet.
• Analysts remain bullish, keeping a "buy" rating and a price target well above current levels, pointing to AI-related demand, advanced chip packaging, and a planned multibillion-dollar expansion in Taiwan and Singapore as reasons for optimism.
• The stock drop happened alongside a broader selloff in Taiwan's market, driven by weak U.S. tech earnings and renewed inflation worries in the U.S.

Outlook: Analysts expect UMC's profitability to improve from 2027 onward as new chip plants come online and pricing power increases, even though near-term margins stay under pressure.