When a Taiwan-listed stock goes ex-dividend, the exchange mechanically deducts the full cash payout from its opening reference price — the drop is arithmetic, not a verdict on the company. Whether the price then climbs back to its pre-ex level is what local investors call tianxi (填息, literally ‘filling the interest’, i.e. filling the ex-dividend gap), and it is the season’s most-watched scoreboard — though, as we will see, total return can turn positive well before a complete fill. Foreign holders face a second deduction the chart never shows: a 21% withholding tax on the cash, so a complete fill banks the net dividend rather than the gross, and true break-even sits lower than the pre-ex price — at the adjusted reference plus the withheld slice of the payout.
The mechanics repeat every summer, and they scale with Taiwan’s biggest names. As of the September 16, 2026 close, TSMC (2330) finished at NT$2,380.00 with the TAIEX at 45,848.90 — and at that price level, TSMC’s quarterly cash payouts are so small relative to the share price that its ex-dates barely register on the chart, while annual high-yielders open visible gaps. That contrast is the thread running through this guide, which covers how Taipei sets ex-dividend reference prices, why the season concentrates in July–September, how to size a gap from published numbers, and what the tax rules mean for foreign holders.
The mechanical drop: how Taipei sets the ex-dividend reference price
Taiwan distinguishes two events that are often blurred in English. Chuxi (除息) is going ex-dividend for a cash payout; chuquan (除權) is going ex-rights for a stock dividend or capitalization issue. For a pure cash dividend, the Taiwan Stock Exchange (TWSE) sets the ex-day reference price with simple subtraction:
- Ex-dividend reference price = previous close − cash dividend per share.
- Stock dividends and combined cash-plus-stock events use a division-based formula instead, because the share count changes.
- Taiwan’s ±10% daily price limit is then computed from this adjusted reference price, not from the previous close.
Two practical consequences. First, on ex-morning your quote screen and many broker P&L views will show a ‘loss’ equal to the dividend that is not a loss at all — the cash is on its way to your account. Second, because the limit bands re-center on the adjusted price, a large dividend shifts the entire day’s tradable range down by the payout amount. Always compute the adjusted reference yourself before judging an ex-day move.
填息 and 貼息: the local scoreboard
A stock is said to have filled its gap — tianxi (填息) — when it trades back up to its pre-ex-dividend close. A complete fill (完全填息) at or above that level means holders have both the cash and an unchanged share price: the dividend has been fully banked. Local media track days-to-fill (填息天數) as a headline statistic each season, and companies with long records of fast fills are marketed to retail investors on that basis.
The mirror-image term is tiexi (貼息): the price falls below the adjusted reference and stays there, so the holder received cash but lost more in market value. The key framing: filling is a price-recovery statistic, not the on/off switch for earning a return. Total return turns positive before a complete fill — as soon as the share price plus the net dividend exceeds where you started — so a price anywhere between the adjusted reference and the pre-ex close can already represent a positive total return. Reading a fill still requires two data points, not one: the pre-ex close (the fill target) and the adjusted reference (the ex-day starting level from which any partial fill is measured). Anything between the two is a partial fill.
Why the season concentrates in summer
Almost all Taiwanese companies run a calendar fiscal year, and company law requires the annual general meeting to be held within roughly six months of year-end. The result is a rigid pipeline: full-year results early in the year, AGMs clustered in May and June to approve payouts, and ex-dividend dates concentrated from late June through September, with the heaviest traffic historically in July and August. TSMC is the prominent exception — it moved to quarterly cash dividends years ago, which is why its ex-dates fall outside the classic cluster and why each individual payment is small relative to the share price.
One index-level trap follows directly. The headline TAIEX is a price index that is not adjusted for dividends. When hundreds of companies go ex within a few summer weeks, the index mechanically sheds points that no one actually lost. TWSE publishes a separate Total Return Index that adds dividends back. Actionable rule: before interpreting soft TAIEX prints during July–September as distribution or foreign selling, compare against the total-return series and check the ex-dividend calendar for mega-caps — a single large ex-date at a heavyweight like TSMC or Hon Hai moves the index on its own.
Cash-heavy payouts: yields you can check daily
Taiwan’s payout culture shifted decisively from the stock dividends of the 1990s to cash over the following decades, and cash now dominates. Taiwanese retail investors treat dividend stocks the way savers elsewhere treat deposit products, which is part of why fill statistics carry so much cultural weight. The TWSE publishes trailing dividend yield, PER and PBR for every listed stock daily. As of the September 16, 2026 close:
| Stock (code) | Close (NT$) | Trailing yield | Foreign ownership |
|---|---|---|---|
| TSMC (2330) | 2,380.00 | 0.92% | 69.19% |
| MediaTek (2454) | 4,530.00 | 1.18% | 56.03% |
| Hon Hai (2317) | 248.00 | 2.89% | 40.32% |
| UMC (2303) | 142.00 | 1.84% | 41.06% |
Note that these are trailing yields based on dividends already paid; after a company announces a higher payout, the published yield lags until the cash actually goes ex. The foreign-ownership column matters for the tax discussion below: the larger the foreign share, the more of each dividend leaves the market as withholding.
Worked example: sizing a gap from the published numbers
Here is how to read the published figures, step by step, using the verified September 2026 data above.
- Find the gap size in percent. TSMC pays cash quarterly, and its trailing yield stood at 0.92% at the September 16, 2026 close of NT$2,380.00. Split across four payments a year, that yield implies an ex-day gap on the order of a quarter of a percent of the share price per payout.
- Compare the gap to a normal day’s range. A move that small is smaller than an ordinary session’s fluctuation in a large-cap semiconductor name. The fill requires nothing unusual to happen — which is why gaps of this size have tended to close quickly.
- Contrast with an annual payer. Hon Hai’s trailing yield of 2.89% on a NT$248 close implies roughly NT$7 of cash per share per year. Paid as a single annual installment, that is an ex-day gap of nearly 3% — an amount that needs a genuine rally, not background noise, to fill.
The general lesson: all else equal, a smaller gap requires a smaller price move to fill. Days-to-fill also depends heavily on volatility, market direction and company-specific news, so gap size is a starting heuristic, not a forecast. Quarterly payers have turned their ex-dates into near non-events; annual high-yielders can take weeks or months to fill, and in weak tapes some never fill within the year — the tiexi outcome. Never read a fast fill at a fraction-of-a-percent-gap stock as evidence that a 5%-gap stock will behave the same way.
Withholding tax basics for foreign holders
The tax layer changes the arithmetic materially for non-residents, and it is invisible on the chart.
- Withholding rate. Cash dividends paid to non-resident foreign investors are withheld at source at a standard 21% rate (as of 2026). Some of Taiwan’s income-tax treaties provide a reduced dividend rate, claimed through your custodian, but the rate and eligibility depend on the specific treaty and its beneficial-owner requirements — confirm against the treaty text and Taiwan Ministry of Finance guidance for your jurisdiction before assuming relief applies.
- No capital gains tax, but a transaction tax. Taiwan levies no capital gains tax on listed shares; instead a 0.3% securities transaction tax applies on the sell side.
- ADRs are not an escape. Dividends on ADRs such as TSM carry the same Taiwan withholding upstream before reaching ADR holders.
- Resident-only charges. The supplementary health-insurance premium (around 2%) on large dividends applies to resident individuals, not foreign investors — do not double-count it.
Now redo the fill math after tax, using the annual payer above. Hon Hai’s roughly NT$7 of yearly cash per share nets a non-treaty foreign holder about NT$5.5, while the reference price still drops the full payout on the ex-date. Break-even therefore sits at the adjusted reference price plus roughly NT$1.5 — the withheld slice — not at the full pre-ex level. An exact fill back to the pre-ex price leaves that holder with the roughly NT$5.5 net dividend fully banked: real return, just about NT$1.5 per share less than a pre-tax reading of the same chart would imply. That wedge is one input into the local practice of qixi (棄息, ‘abandoning the dividend’) — selling ahead of the ex-date to avoid the withholding, then buying back after — though whether it pays in practice also depends on the 0.3% transaction tax the sale itself incurs. The practical threshold to remember: for a foreign holder, break-even requires the price to recover only the withheld portion of the gap — the tax rate times the dividend — not the whole gap, and a complete fill delivers the net dividend, not the gross.
Where to check ex-dates and fill data
- MOPS (Market Observation Post System) carries the official board announcements of dividend amounts and ex-dates.
- TWSE publishes the ex-day reference prices before the open, plus the daily yield/PER/PBR table used above.
- TPEx applies the same mechanics for OTC-listed companies.
FAQ
Does a Taiwan stock have to fill its ex-dividend gap?
No. There is no mechanical force pulling the price back; tianxi is a descriptive statistic, not a rule. A stock that stays below its adjusted reference (tiexi) has delivered a negative total return despite paying cash, and some high-yield names spend entire years unfilled.
When exactly is Taiwan’s dividend season?
AGMs cluster in May–June because of the six-month statutory deadline, and ex-dividend dates run from late June through September, historically peaking in July–August. Quarterly payers such as TSMC go ex four times a year, outside the classic cluster.
How much tax do foreign investors pay on Taiwan dividends?
The standard non-resident withholding rate is 21% (as of 2026), deducted at source. Reduced rates are available under some of Taiwan’s tax treaties, subject to each treaty’s terms and beneficial-owner requirements. There is no capital gains tax on listed shares; a 0.3% securities transaction tax applies when you sell.
Why does the TAIEX drop on big ex-dividend days?
Because the headline TAIEX is not adjusted for dividends, a heavyweight going ex removes index points mechanically. Use TWSE’s Total Return Index to separate real selling from calendar arithmetic.
Sources
- TWSE market data and daily yield/PER/PBR tables — www.twse.com.tw/en and openapi.twse.com.tw
- MOPS corporate filings (dividend announcements, ex-date notices) — emops.twse.com.tw
- TPEx (OTC-listed equivalents) — www.tpex.org.tw
- TSMC investor relations (quarterly dividend schedule) — investor.tsmc.com
- Taiwan Ministry of Finance (non-resident withholding rules and tax-treaty list) — www.mof.gov.tw
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.