A 1,374-point break below 42,000
The TAIEX never recovered from its opening gap on Thursday. The index opened 282.78 points lower at 42,666.13 and slid through the session to close down 1,374.19 points, or 3.20%, at 41,574.72 — below the 42,000 mark for the first time since late July. Turnover was heavy at NT$926.02 billion.
The trigger was Wednesday’s U.S. session, where the Philadelphia Semiconductor Index fell 3.13% on renewed questions about the returns on massive AI capital spending — and on the prospect of tighter regulatory scrutiny of AI data centers after the Democratic Party took control of Congress in the midterms. Notably, the broader S&P 500 rose 1.58% the same night; this was a chip-specific storm, and Taiwan, the most chip-concentrated major market in the world, took it accordingly. Overnight S&P futures were only modestly softer at 7,708.50 (-0.16%), so Thursday’s damage in Taipei ran well beyond what the U.S. setup alone would imply — the local flow picture explains the rest.
Institutional flows: foreigners sell NT$102.5 billion
Thursday’s exchange data showed one of the heavier foreign selling days of the year, extending a multi-day withdrawal:
| Investor group | Net trading value (Nov 5) | Direction |
|---|---|---|
| Foreign investors | NT$-102.46B | Net sell |
| Investment trusts | NT$+22.53B | Net buy |
| Dealers (prop + hedge) | NT$-43.53B | Net sell |
| Three institutions combined | NT$-123.46B | Net sell |
Domestic investment trusts were the only net buyers among the three major groups, absorbing NT$22.53 billion against the tide. The currency told the same story: USD/TWD was quoted around 32.94 on Nov. 5, with the Taiwan dollar touching 32.965 intraday — its weakest level in more than 18 months — as equity outflows pressed it toward the psychological NT$33 line.
Semiconductors: TSMC holds, the second tier doesn’t
The dispersion inside the chip complex was the day’s most striking feature. TSMC (2330) fell just 0.88% to NT$2,240 — a clear outperformance of the tape. The pain concentrated in IC design and the second tier: MediaTek (2454) plunged 6.86% to NT$3,460, UMC (2303) dropped 6.73% to NT$98.40, and Hon Hai (2317) lost 2.08% to NT$235. High-priced design names such as Global Unichip and MPI fell sharply, and the AI server supply chain — Quanta, Auras, Jentech, Kaori, Elite Material — saw steep declines or limit-downs. The population of “thousand-dollar stocks” shrank to 39. The official sector tape added a twist: the TWSE Semiconductor index actually rose 2.56% on the day — ahead of shipping’s 1.30% and financials’ 0.41% gains — a capitalization-weighted reading that sits at odds with the breadth of single-stock chip losses and says more about index weighting than about broad strength in the sector.
Valuation goes some way to explaining the pattern. MediaTek entered Thursday at 61.4x trailing earnings and 14.0x book — the richest of the heavyweights — versus TSMC at 26.2x and 9.1x. When the market questions AI monetization, the names priced most aggressively for it fall hardest.
On the ADR side, TSM closed Wednesday’s U.S. session at $395.75, roughly 16.4% above Thursday’s Taipei close on a share-adjusted basis. That gap sits comfortably inside the structural 15–25% premium ADRs have carried in recent years, and the two closes come from different sessions — nothing anomalous there. Day-to-day changes in that gap are the signal to track if selling persists, not the level itself.
Positioning: three channels, read separately
Derivatives and leverage data lag by a session, so the following describes the setup coming into Thursday, not Thursday’s own positioning. As of Wednesday’s TAIFEX data, foreign investors held a net short of 93,647 contracts in TAIEX futures open interest (that day’s net volume was a modest -1,860 contracts), and the volume-based put/call ratio stood at 85.00% — foreigners were already hedged short in size before the break.
Taiwan’s leverage channels each told a consistent, if quiet, story as of Wednesday:
- Retail leveraged longs (margin purchases): the market-wide balance stood at NT$596.9B, down NT$2.83B — retail was trimming, not adding, into the weakness. At the stock level, though, bargain-hunting was visible: TSMC margin balances rose 798 lots, UMC rose 1,902 lots, and MediaTek rose 206 lots, while Hon Hai’s fell 406 lots.
- Institutional shorts (SBL balances): short balances rose in 629 shortable issues against 297 declines — broad institutional pressure. Hon Hai’s SBL balance rose about 2.1 million shares, UMC’s about 1.9 million, and TSMC’s about 0.9 million on the day.
- Retail shorts (margin shorts): small and shrinking in the large caps — TSMC’s margin short balance fell to just 16 lots.
The combination — heavy foreign cash selling, a large pre-existing foreign futures short, broadening institutional SBL shorts, and retail cautiously stepping in with leverage on the big names — is a classic stress configuration. It is not yet capitulation: the put/call ratio at 85% and a modest margin-balance decline suggest orderly de-risking rather than panic.
What to watch
- Thursday’s (Nov 5) TAIFEX data, when published: whether foreign futures net open interest extended beyond -93,647 contracts into the break, and whether the put/call ratio jumped from 85%.
- USD/TWD at the NT$33 line: a decisive break above 33 would confirm the outflow pressure is persisting rather than a one-day event.
- Monthly revenue filings, due November 10: October sales from TSMC and the AI supply chain are the first hard data that can either validate or push back on the AI-capex anxiety driving this sell-off.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.