UMC stock gains 3.33 percent as chip shares rally

Published on 09/22/2026 at 13:37 | Editorial responsibility: Rafael Müller, Editor-in-Chief AD HOC NEWS

UMC stock closed at USD 25.43 on September 21, 2026, up 3.33 percent as Nasdaq reached a record close. Second-quarter gross margin rose to 32.5 percent.

UMC, US9042181029, Illustration mit AI erstellt.

United Microelectronics Corp. (US9042181029) closed at USD 25.43 on the Nasdaq on September 21, 2026, up 3.33 percent from the previous session. The move came as semiconductor shares advanced and the Nasdaq Composite reached 27,122.09 points, a gain of 2.26 percent on the same date.

Margin improves in Q2

UMC's operating picture strengthened in the second quarter of 2026. According to Yahoo Finance on September 21, 2026, gross margin increased to 32.5 percent from 29.2 percent in the first quarter and 28.7 percent in the year-earlier quarter.

The comparison gives the margin a 3.3 percentage-point sequential improvement and a 3.8 percentage-point year-over-year improvement. The cited report attributes the change to higher wafer shipments and better capacity utilization, making utilization a central operating variable for the current earnings picture.

Chip demand lifts the sector

The broader sector supplied the immediate market backdrop. The Nasdaq Composite added 2.26 percent to 27,122.09 points on September 21, 2026, while semiconductor shares benefited from renewed demand for artificial-intelligence hardware. UMC's 3.33 percent rise therefore exceeded the index move by 1.07 percentage points.

UMC also faces a competitive margin comparison within foundry manufacturing. The same September 21, 2026 report said TSM's second-quarter gross margin reached 67.7 percent, up 1.5 percentage points sequentially and 9.1 percentage points year over year. UMC's improvement is material, but its 32.5 percent margin remains below that larger rival's reported level.

Stock closes at USD 25.43

UMC stock finished at USD 25.43 on the Nasdaq on September 21, 2026, with a daily gain of 3.33 percent. For investors, the key measured change is the combination of a 32.5 percent second-quarter gross margin and a 3.8 percentage-point year-over-year expansion.