The TAIEX share index lost 51.35 points to close at 5,860.30, giving back part of last week's nearly 5 percent bounce from a 14-month low.
Compal, one of Taiwan's largest mobile phone makers, dropped the 7 percent daily trading limit to T$94.00 after reporting October sales of T$2.98 billion, down from the previous month's T$3.05 billion.
Most other monthly sales results were positive, but local investors preferred to keep to the sidelines due to worries over bird flu and political infighting ahead of year-end mayoral and county elections, as well as the end of the seasonal tech boom.
"The sales numbers have been good, but these stocks have already had good runs, and also the electronics season is peaking, so why buy now?," said Michael McGregor, vice president in charge of International Sales at PrimAsia Securities.
Other handset-related shares, one of this year's best-performing sectors, lost ground along with Compal Communications.
Smartphone maker High-Tech Computer slipped 0.62 percent, while Green Point Enterprises Co Ltd fell 6.83 percent and mobile phone screen maker Wintek slipped 3.83 percent to T$43.95.
Mediatek Inc, the world's largest designer of DVD chips, reversed early losses and closed 0.63 percent higher at T$317 after reporting October sales jumped 43.1 percent from the same month last year.
United Microelectronics Corp, the world's second-largest contract microchip maker, was the most actively traded issue and fell 3.63 percent ahead of reporting October sales on Tuesday.
Tourism shares were strong performers after China's top tourism official invited Taiwan industry representatives to visit and discuss Chinese tourists travelling to Taiwan.
Hotel chain operator Ambassador Hotel added 1.29 percent to close at T$23.50, lifting the tourism sub-index 0.37 percent higher.