UMC · United Microelectronic

The thesis

United Microelectronics is more likely to lag the S&P 500 over the next three months. The company delivered the quarter it guided, but flat fourth-quarter gross margin guidance and a rebound that has not reached the 200-day average leave the re-rating unproven. November net sales, due by 10 December 2026, decide the next read.

UMC's 28 October 2026 report showed third-quarter gross margin of 34% and utilization of 92%. Management guided fourth-quarter gross margin comparable to the third (UMC Q3 release; Zacks summary).

The American depositary share (ADS) closed at $15.76 on 12 November 2026. That is 45.6% below the quoted 52-week high of $28.96 (intraday, 25 June 2026) and up from $13.38 on 5 November 2026. The price already reflects a flat margin outlook, dilution from the October convertible and a sector sell-off: a 5 November 2026 headline described chip stocks' worst day since 2020, with 28 of the 30 biggest names in a bear market.

Bullish and bearish views on United Microelectronic Corp.

The bull case on United Microelectronic Corp. (UMC), in brief: the guided quarter was delivered. The bear case: margin landed at the low end of the guide.

Bull case

• The guided quarter was delivered. Third-quarter 2026 revenue was NT$74.24 billion, up 8.0% from NT$68.73 billion in the second quarter and up 25.6% from a year earlier. Gross margin rose to 34% from 32.5%, and utilization to 92% from 85% (UMC Q3 release, 28 October 2026).
• Operating profit rose faster than sales. Operating income was NT$18.64 billion, up 24.7% from the previous quarter, for a 25.1% operating margin against 21.8% in the second quarter (UMC Q3 release, 28 October 2026).
• Utilization is guided to stay high. Management guided fourth-quarter utilization in the low-90% range, firm US-dollar average selling prices and wafer shipments up a low-single-digit percentage (UMC Q3 release, 28 October 2026).
• Monthly sales are still growing. October net sales were NT$25.20 billion, up 18.33% from NT$21.29 billion a year earlier. January–October sales were NT$229.21 billion, up 16.33% (UMC monthly sales announcement, 5 November 2026).
• Customer work continues. UMC and AP Memory announced a deep-trench-capacitor power-delivery collaboration for artificial intelligence and high-performance computing on 22 October 2026.

Bear case

• Margin landed at the low end of the guide. Management's 29 July 2026 guide was 34% to 36%, and the reported 34% sits at its bottom. Fourth-quarter gross margin is guided only as comparable to the third.
• Estimates were missed. Benzinga reported third-quarter earnings of $0.21 per ADS against a $0.23 estimate, and sales of $2.320 billion against $2.350 billion, on 28 October 2026.
• The margin ceiling looks lower. Per a summary of the call, depreciation is set to rise at a low-teens pace for years, raw-material costs are climbing, and the chief financial officer said gross margin is unlikely to regain prior-cycle peaks above 40%.
• Sales growth is slowing. October's 18.33% rise from a year earlier compares with 27.22% in September and 30.71% in August. October's NT$25.20 billion is below September's NT$25.35 billion (UMC monthly sales announcements).
• Dilution and insider selling. The US$1.8 billion zero-coupon convertible issued 13 October 2026 adds about 2.34% to the share count if fully converted. Chief financial officer Liu Chitung reported selling 1,600,000 common shares between 16 September 2026 and 17 September 2026 at an average of NT$143.00, and Vice President Lin Jen-Tsung sold 10,000 shares on 22 September 2026 (SEC Form 4 filings).

Price setup

The ADS closed at $15.76 on 12 November 2026, after $16.08 on 11 November 2026, $15.04 on 10 November 2026, $14.89 on 9 November 2026, $13.85 on 6 November 2026 and $13.38 on 5 November 2026. The 3-month change is –17.7%, measured from the adjusted close of $19.15 on 14 August 2026.

The 200-day moving average is $17.16 and the 50-day moving average is $20.88, both on adjusted closes as of 12 November 2026. The shares sit under both. The 52-week closing low was $7.02 on 17 November 2025, so the shares remain well above their level of a year ago despite the fall from the June high.

The ADS represents five Taiwan-listed common shares and prices off Taiwan's prior close, so the Taiwan session drives each US open. The observable supply is the convertible and the September officer sales; the first date the convertible can convert is estimated at 13 January 2027.

Catalysts ahead

• ~7 December 2026 (est.): November 2026 net sales announcement, due by 10 December 2026 under Taiwan disclosure rules. Shows whether sales hold near the NT$25 billion monthly run rate that supports the guided fourth quarter.
• ~10 December 2026 (est.): Taiwan foundry peers' November sales reports. Shows whether the sector drawdown is tracking operating data or running ahead of it.
• ~13 January 2027 (est.): Conversion window opens on the 13 October 2026 convertible bonds. Sets when up to 2.34% dilution can begin to reach the share count.

What would change the view

A daily close above $20.92, just above the 50-day average, which would show the shares leading the S&P 500 again and prove this lag call wrong.

What it trades with

UMC trades with Taiwan and global foundry shares. The 5 November 2026 chip sell-off shows how a sector move can override company data. Each ADS tracks the Taiwan line (2303.TW), which has a ±10% daily price limit that the ADR does not. Mature-node peers' pricing and utilization read across to UMC's margin. Non-operating investment income can be a large share of net income, so operating margin is the cleaner profitability series.