Taiwan Stocks Lose the 46,000 Level as Substrate and Memory Names Slide

The TAIEX swung 678 points to close down 307, with 1,423 decliners, even as Korean shares rose more than 1% and US indices had closed higher

A man walks past a board showing numbers of the TAIEX Index (C) and other markets at the Taiwan Stock Exchange in Taipei on May 4, 2026. I-Hwa Cheng / AFP via Getty Images

TAIPEI — Taiwan's benchmark index fell below 46,000 on Thursday, reversing an early advance and closing lower even as regional peers rallied.

The TAIEX closed down 307.06 points at 45,857.66, on turnover of NT$946.2 billion. Some 1,423 issues declined.

The session was volatile. The index opened up 160.76 points at 46,325.48 and extended gains to 46,517, led by memory, low-Earth-orbit satellite and other electronics names, with traditional industries and financials adding support. It then turned lower as selling emerged in semiconductors, silicon intellectual property, ABF substrates and optoelectronics, testing 45,839 before recovering slightly. The intraday range was 678 points.

Taiwan Semiconductor Manufacturing Co. and financial shares limited the decline.

The divergence is the notable part.

All four major US indices closed higher on Wednesday, and Asian markets followed on Thursday, with South Korean shares gaining more than 1%. Taiwan opened in line with that move and then broke from it.

The selling concentrated in the AI packaging and substrate supply chain rather than in the largest names.

Nan Ya Printed Circuit Board closed limit down at NT$1,080 on turnover of NT$23.77 billion. Unimicron fell NT$50 to NT$923. Kinsus dropped NT$72 to NT$775, and Zhen Ding Technology fell NT$43 to NT$464.

Memory was mixed to weaker. Nanya Technology was the day's most heavily traded stock, falling NT$40.50 to NT$477.50 on NT$58.66 billion of turnover. Winbond Electronics fell NT$10 to NT$169.

Against that, the two largest names rose. MediaTek gained NT$65 to NT$4,340, and TSMC added NT$5 to NT$2,390.

That split matters more than the index level.

ABF substrates and advanced packaging sit immediately downstream of chip fabrication in the AI hardware chain. When those names fall hard while TSMC and MediaTek hold, the market is repricing the parts of the supply chain with less pricing power rather than questioning AI demand itself.

Nan Ya PCB hitting its daily limit is the sharpest signal in the session. Limit-down moves in a large-cap substrate maker are not routine.

Taiwan's market has risen roughly 90% over the past year, making it the world's fifth-largest by value, with gains concentrated in AI-linked names. A one-day rotation does not undo that. It does indicate where the crowding is.