Taiwan stocks gave up early gains to end lower on Thursday as lingering concerns over weak corporate earnings in Taiwan and the United States drove cautious investors away from tech shares like Nanya Tech.
The main TAIEX share index was trapped in a tight range before ending down 0.25 percent at 5,713.39. But the index was still up nearly 1 percent from a two-week low on Monday.
The soft turnover of T$54.33 billion, flat with Wednesday's, reflected the cautious mood ahead of upcoming second-quarter corporate earnings reports from major US and Taiwan firms.
Shares in Nanya Tech, a maker of memory chips, fell 0.79 percent to T$25.00 and those of rival Winbond were off 0.67 percent at T$14.80, ignoring a 1.12 percent advance on the Philadelphia semiconductor index on Wednesday.
The financial sector edged down 0.09 percent.
Hua Nan Financial Holding Co shares lost 0.73 percent to T$27.20 even after the company posted an 11.7 percent rise in first-half net profit on Wednesday.
Microchip issues had been week in recent sessions after some foreign investment banks were bearish about third-quarter earnings of the sector giant Intel Corp.
But Taiwan Semiconductor Manufacturing Co (TSMC), the market's most heavily weighted stock, finished up 0.67 percent at T$45.00.
The world's top contract chipmaker announced minutes after close of trade that June sales rose 26.2 percent to record high, a day after rival United Microelectronics Corp (UMC) reported a 47 percent year-on-year rise in June sales. UMC shares were flat at T$23.80. AU Optronics Corp, the world's third-largest display screen maker, jumped 0.21 percent to T$47.90, extending Wednesday's 1.27 percent gain.
The stock outperformed the rest of the tech sector on Wednesday after the company gave an upbeat view on second half product prices in a Reuters interview.