Taiwan stocks fell 0.46 percent on Thursday, coming off a 14-month closing high, as early gains for tech firms like Quanta on the back of a US advance and lower oil prices were given back. The TAIEX share index ended down 0.46 percent, or 29.78 points, at 6,394.03 points, after gaining as much as 0.85 percent in earlier trading.
"Electronics have been the main motor for the recent rally, but they couldn't maintain their momentum," said Chiang Chen-sheng, a manager at Masterlink Investment Advisory.
Quanta Computer Inc, the world's largest contract maker of laptop computers, ended down 0.16 percent at T$62.40, after soaring as much as 2.56 percent.
While that up-then-down pattern was repeated for many electronic issues - the tech subindex ended up a slim 0.08 percent after jumping 1.8 percent in intraday trading - display screen makers fared better than most.
AU Optronics Corp, the world's third largest display-screen maker, added 3.86 percent to T$51.10.
However, the tech index has still gained 21 percent since a low was hit in late April.
Most sectors lost ground, on worries Beijing could accelerate measures to slow its buoyant economy, which continued to expand at a surprisingly fast pace in the second quarter.
Those worries helped cool trading volume to T$113.6 billion, from the nine-month high of T$123.6 billion on Wednesday.
The food, auto, financial, cement and plastics sectors all lost over one percent.
The over-the-counter market's TAISDAQ index gained 0.15 percent to close at 131.25, while the August TAIEX futures index lost 0.3 percent to 6,365.