A brutal close for the AI trade’s home market
The TAIEX fell 6.47% to 42,671.27 at Friday’s 13:30 close — one of the heaviest single-day losses in the index’s recent history. The trigger was external and unambiguous: the Philadelphia Semiconductor Index sank 4.29% in Thursday’s US session, part of a broadening rotation out of technology as investors question whether massive AI infrastructure spending will convert into near-term profits. Taipei, home to the world’s most concentrated semiconductor complex, absorbed that skepticism at full force. The sell-off was regional — Japan’s Nikkei 225 also plunged more than 5% — and was aggravated by risk-off sentiment around rising US–Iran tensions.
The heavyweight damage was severe and indiscriminate:
| Stock | Friday close (NT$) | Change |
|---|---|---|
| TSMC (2330) | 2,290.00 | -7.29% |
| MediaTek (2454) | 3,370.00 | -8.92% |
| UMC (2303) | 144.00 | -10.00% (limit-down) |
| Hon Hai (2317) | 234.00 | -3.51% |
The TSMC move is the story within the story. The company reported a record second-quarter net profit, up 77% year on year, yet the stock fell more than 7% as attention shifted to rising capital-expenditure forecasts and the cost of overseas expansion. When a record quarter cannot hold a stock up, the market is repricing the multiple, not the earnings. UMC’s limit-down close, alongside limit-downs in names like Yageo and Nan Ya Plastics, shows how little discrimination there was in the selling.
Institutional flows: foreigners were already leaving
Friday’s flow data will not be published until after this briefing, but Thursday’s official TWSE figures show the pressure was building before the break:
- Foreign investors: net SELL of NT$48.33 billion — a heavy outflow even by recent standards.
- Investment trusts: net BUY of NT$8.65 billion — domestic funds leaning against the tide, as they often do.
- Dealers (proprietary + hedge): net SELL of NT$3.36 billion.
- Three institutions combined: net SELL of NT$43.05 billion.
The derivatives picture heading into Friday told the same story. As of Thursday’s session, foreign investors held a net short position of 84,453 contracts in TAIEX futures open interest (net volume on the day: -3,207 contracts), and the options put/call ratio stood at 93.37% on open interest and 88.01% on volume. To be clear: these are previous-session readings and describe the posture going into Friday, not Friday’s activity itself — but they show foreign accounts were positioned defensively before the plunge, not caught flat-footed by it.
Leverage and shorts: three channels, three different reads
Taiwan’s leverage data comes through three distinct channels, and Thursday’s readings (the latest available) diverge in interesting ways.
Retail leveraged longs (margin purchases): the market-wide margin loan balance sat at NT$615.6 billion, up a marginal NT$0.19 billion — retail leverage was essentially flat into the crash, neither piling in nor deleveraging. Notably, UMC’s margin balance rose 3,643 lots while TSMC’s fell 375 lots, suggesting retail buyers were rotating down the cap scale.
The institutional short channel (SBL): securities-lending short balances rose in 427 issues and fell in 476 on Thursday — no broad-based institutional short build. UMC’s SBL balance actually dropped 10.34 million shares and MediaTek’s fell 92,000, consistent with shorts covering into weakness. Hon Hai was the exception, with SBL balance up 1.84 million shares.
Retail margin shorts remain small in the large caps — TSMC’s short balance is just 38 lots. The takeaway across all three channels: Friday’s plunge was driven by long liquidation, chiefly foreign, rather than aggressive fresh shorting.
The currency squeeze and the ADR gap
The Taiwan dollar weakened alongside equities, with USD/TWD closing at 32.34, up 0.40% — the currency breached the NT$32.3 level intraday, its weakest in over 14 months, as foreign investors sold local assets and converted proceeds to US dollars. Equity outflows and currency weakness are feeding each other.
On the ADR side, TSM closed Thursday’s US session at $409.74, which stands 15.7% above Friday’s Taipei close on a five-shares-per-ADR basis. That level is within the roughly 15–25% structural premium the ADRs have carried in recent years, and the two closes come from different sessions — so the gap itself signals nothing unusual. Given the overnight SOX rout landed on Taipei after the ADR close, watch how the gap changes once New York reopens; the day-to-day move in the spread is where the information is.
Valuations heading into the sell-off
As of Thursday’s TWSE close — before Friday’s drop — valuations were elevated by historical standards: TSMC at 33.2x earnings and 10.9x book, MediaTek at 59.0x earnings, UMC at 40.2x, and Delta Electronics at 70.2x. Hon Hai, at 17.2x earnings and a 2.96% yield, is the value outlier among the big caps. Friday-updated multiples are not yet available, but the starting point helps explain the violence of the repricing. Foreign ownership remains deep — 69.5% of TSMC and 55.5% of MediaTek — which is precisely why sustained foreign repatriation moves this market so violently.
What to watch
- Friday’s official flow data (published after the close): whether foreign net selling accelerated beyond Thursday’s NT$48.33 billion, and whether investment trusts kept absorbing supply.
- USD/TWD around 32.3: a decisive break higher would confirm the repatriation loop is still running; stabilization would be the first sign of exhaustion.
- The overnight US session: S&P 500 futures were pointing 0.88% lower at 7,511 as Taipei closed. Another leg down in the SOX would test Friday’s lows on Monday; a bounce, and the TSM ADR gap’s direction, will set the tone for the reopen.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.