The TAIEX climbed 439.10 points, or 0.96%, to close Thursday at 46,288.00, reclaiming the 46,000 mark and its monthly moving average after touching 46,874.84 intraday. Turnover expanded to NT$819.4 billion. The story of the day was relief: the Federal Reserve’s 25-basis-point hike on Wednesday, to a 3.75%–4.00% target range, removed a policy overhang that had kept buyers on the sidelines. Wall Street’s own cash session closed mixed to lower — the Dow fell 1.2%, the S&P 500 lost 0.45% to 7,551.81 — but S&P 500 futures rallied 1.63% to 7,679.50 during Asian hours, and Taipei traded off the futures, not the tape.
Semiconductors lead; MediaTek the outlier
The Philadelphia Semiconductor Index had added 0.63% overnight, and Taipei’s chip complex ran with it: the TWSE Semiconductor sub-index gained 1.51%, alongside Shipping (+1.93%) and Financials & Insurance (+0.44%). TSMC (2330) rose NT$45, or 1.89%, to NT$2,425, extending momentum after filling its ex-dividend gap in just 27 minutes on Wednesday. UMC (2303) was the standout among the heavyweights, up 3.87% to NT$147.50. Hon Hai (2317) added 1.01% to NT$250.50 and Quanta (2382) climbed NT$3.5 to NT$344, with AI supply-chain interest still centered on the Taiwan Silicon Photonics Industry Alliance work that followed SEMICON Taiwan. MediaTek (2454) was the exception, surrendering intraday gains to close down NT$30, or 0.66%, at NT$4,500 — at a trailing PER of 74.81 as of Wednesday’s TWSE data, the richest valuation among the big five, so some profit-taking into strength is not a shock.
Institutional flows: all three camps buying
| Investor type | Net trading value (Sept 17) |
|---|---|
| Foreign investors | NT$+12.19B (net buy) |
| Investment trusts | NT$+7.71B (net buy) |
| Dealers (prop + hedge) | NT$+1.58B (net buy) |
| Combined | NT$+21.48B |
Direction was unambiguous: all three institutional camps bought. Foreign investors, who already hold 69.19% of TSMC and 56.03% of MediaTek, put NT$12.19 billion to work. Investment trusts added a substantial NT$7.71 billion, and even the dealer number — NT$5.89 billion of outright proprietary buying against NT$4.32 billion of hedging sales — netted out positive. A NT$21.5 billion combined bid on an 800-billion-plus turnover day is conviction, not drift.
Leverage and the short channels — previous-session data
Taiwan runs three distinct leverage and short channels, and Wednesday’s figures (the latest published; Thursday’s arrive with a one-day lag) show them pulling in different directions. Market-wide margin purchases — the retail leveraged-long channel — rose NT$3.93 billion to NT$586.2 billion, with UMC’s margin balance up 4,879 lots to 198,616. In the SBL channel — the institutional short route, distinct from retail margin shorts — balances rose in 526 shortable issues and fell in 386. The stock-level detail is more interesting than the breadth: TSMC’s SBL balance fell 1.93 million shares to 14.68 million, institutional shorts trimming into strength, while UMC’s jumped 8.24 million shares to 69.3 million and Hon Hai’s rose 2.18 million. Those UMC and Hon Hai builds predate Thursday’s rally, which then ran directly against them — Thursday’s SBL print, once published, will show whether that fresh positioning covered or dug in. Taken together with today’s flows, the positioning picture is a market leaning long — institutional cash buying, modestly rising retail leverage — but with the institutional short channel still active in the foundry names rather than one-sidedly bullish.
Currency and the ADR gap
The New Taiwan dollar softened slightly, with USD/TWD at 31.87, up 0.30% on the day — mild depreciation despite the foreign net buy, and worth noting with the central bank’s quarterly board meeting expected today (the CBC typically meets the third Thursday of quarter-end months), its outcome landing after the 13:30 cash close. On the ADR side, TSM closed Wednesday in New York at $417.72, about 9.8% above Thursday’s Taipei close on a five-share basis. That level says little by itself: the ADR habitually carries a structural premium — roughly 15–25% in recent years, reflecting limited fungibility — and the two closes come from different sessions, so Taipei’s Thursday rally mechanically compresses the snapshot. The signal, as always, is in how the gap moves over the coming sessions, not where it sits.
What to watch
- The CBC decision and TWD guidance. With the Fed having just hiked to 3.75%–4.00% and USD/TWD drifting to 31.87, the central bank’s rate call and currency commentary are the next catalyst.
- Thursday’s margin and SBL data, published with a lag. Specifically whether UMC’s freshly built 69.3-million-share institutional short balance covered into the stock’s 3.87% rally, and whether the TSMC short-trimming continued.
- Follow-through on the futures signal. Taipei bought the 1.63% S&P futures rally before the US cash session could confirm it; foreign flow on Friday will show whether that confidence was rewarded.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.