United Microelectronics is trading 4.7% up at $21.74, appearing primarily sector-driven amid a broader semiconductor-sector rally. - It opened on September 8, 2026, above the September 4 close of $20.77; Asian semiconductor shares rallied strongly while major U.S. indices were slightly lower. - August revenue rose 30.71% to NT$25.04 billion, but no source explicitly links the announcement to the move. - Momentum remains elevated after a 4.58% gain on September 4; confidence is medium.