Monday’s session in Taipei was a tale of two tapes. The TAIEX opened heavily lower in sympathy with Friday’s US tech rout, plunged more than 940 points intraday to 46,170 — briefly breaching 47,000’s former support zone and the quarterly moving average — and then spent the afternoon repairing the damage. By the 13:30 close the index was down 289.18 points, or 0.61%, at 46,822.08, holding the quarterly line on turnover of NT$825.10 billion. Given that the Philadelphia Semiconductor Index had dropped 3.83% and the S&P 500 1.09% in Friday’s US session, a 0.61% loss counts as a controlled outcome.
TSMC’s final-tick rescue
The index recovery ran through one stock. TSMC (2330) traded as low as NT$2,390, down 1.24% intraday, before a final-tick buy order exceeding 4,000 lots lifted the shares back to close exactly unchanged at NT$2,420. That single print was enough to drag the TWSE semiconductor sub-index to a positive close, up 0.24% on a down day for the broader market. The rest of the heavyweight complex did not get the same treatment: Hon Hai (2317) fell 1.84% to NT$239.50, MediaTek (2454) lost 1.06% to NT$4,205, UMC (2303) slipped 1.13% to NT$131.50, and Quanta (2382) dropped 2.33% to NT$314.50.
Institutional flows: heavy foreign selling, trusts lean in
Official exchange data for Monday, October 19 (net trading value, all three institutional groups):
| Investor group | Net flow (NT$) | Direction |
|---|---|---|
| Foreign investors | -76.74B | Net sell |
| Investment trusts | +23.05B | Net buy |
| Dealers (proprietary + hedge) | -36.26B | Net sell |
| Combined | -89.95B | Net sell |
The pattern is familiar from stress days: foreign money exits in size, domestic investment trusts absorb some of the supply, and dealer books reduce risk alongside the foreigners. A combined NT$89.95 billion of institutional net selling against a 0.61% index decline implies meaningful demand showed up elsewhere — consistent with the bargain-hunting seen off the morning low.
The currency is now part of the story
The Taiwan dollar weakened past the psychological 32.5 level intraday to an 18-month low of 32.55 per US dollar, with USD/TWD finishing Monday at 32.47, up 0.43%. The move drew a rare intraday statement from the central bank, which disclosed that foreign investors net sold US$19.402 billion of Taiwan equities and remitted out US$17.961 billion between October 12 and October 16 — a span over which the TWD depreciated 1.37% — and pledged to maintain “dynamic stability.” The equity outflow and the currency slide are two expressions of the same repatriation flow, and the central bank is now publicly flagging it.
Positioning backdrop (previous-session data)
Monday’s derivatives and leverage data are not yet published, so the latest reads are from Friday, October 16, and describe the setup coming into the session rather than today’s response:
- Futures: foreign investors held TAIEX futures net open interest of -93,675 contracts as of Friday — a substantial net short book heading into this Wednesday’s October final settlement.
- Options: the volume-based put/call ratio stood at 88.75% on Friday, below the 100 line.
- Retail leverage: the market-wide margin loan balance (retail leveraged longs) was NT$645.6 billion as of Friday, down a marginal NT$0.82 billion — no sign of forced deleveraging yet, but Monday’s figure will be the one to check.
- Institutional shorts (SBL channel): securities-lending short balances rose in 373 issues and fell in 502 on Friday. At the single-name level, Hon Hai’s SBL balance rose by 3.96 million shares while UMC’s fell by 3.19 million — the institutional short channel was rotating, not uniformly pressing.
ADR gap worth a glance
TSMC’s ADR closed Friday’s US session at $412.61, roughly 10.7% above Monday’s Taipei close on a five-share basis. The ADR premium is structural — it has run roughly 15–25% in recent years given limited fungibility — and the two closes are from different sessions, so the level itself signals nothing. But a gap sitting below the recent range after a heavy US semiconductor selloff is the kind of compression that tends to resolve in the next overlapping sessions, and with S&P 500 futures up 0.74% overnight, Tuesday’s Taipei open has a friendlier setup than Monday’s did.
Under the surface
Beyond the headline names, the weak spots were passive components — Prosperous Dielectric limit-down on resumption after a capital reduction, with Yageo and Walsin Technology lower — plus memory names (Nanya Tech, Winbond, ADATA), Formosa Plastics group shares, and biotech. Against that, PCB stocks rallied on exhibition catalysts with several smaller names limit-up, shipping gained 1.89%, and financials rose 0.94% — old-economy and domestic sectors cushioning a tech-led decline.
What to watch
- Wednesday’s TAIFEX final settlement (October 21): foreign investors carried a -93,675-contract net short in TAIEX futures into this week (Friday’s data); how that book resolves into settlement is the week’s key positioning event.
- Monday’s TAIFEX and margin data, published Tuesday: whether foreign futures shorts were covered into the intraday low, and whether retail margin balances finally cracked after the 940-point scare.
- USD/TWD around 32.5: the central bank has publicly committed to smoothing; a stabilizing currency would be the first sign the foreign repatriation flow — NT$76.74 billion of cash-equity selling on Monday alone — is slowing.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.