Compliance
Taiwan’s Provisional Tax Filing for Profit-Seeking Enterprises: Best Practices for September
With Taiwan’s provisional income tax filing period for profit-seeking enterprises opening September 1-30, 2026, and the e-filing software available from August 15, this article helps entities prepare properly and avoid costly mistakes.
By NomadicTax Research Team • 5-8 min read • August 31, 2026
## What the Announcement Is
On **August 12, 2026**, the Ministry of Finance (Taiwan) announced that for the fiscal year 2026, profit-seeking enterprises must file their **provisional income tax returns** between **September 1 and September 30**. E-filing and tax payment software becomes available on **August 15**.([mof.gov.tw](https://www.mof.gov.tw/Eng/singlehtml/f48d641f159a4866b1d31c0916fbcc71?cntId=61ab0bb237564e1ca593dea59501b1d9&utm_source=openai))
### Key Filing Requirements
- Applies to **profit-seeking enterprises** except those with special fiscal years.
- All supporting documents (investment tax credit certificates, CPA-audited reports, etc.) that require stamps or seals must be in PDF format and uploaded via the e-filing system by **September 30**.([mof.gov.tw](https://www.mof.gov.tw/Eng/singlehtml/f48d641f159a4866b1d31c0916fbcc71?cntId=61ab0bb237564e1ca593dea59501b1d9&utm_source=openai))
- For those who prefer or need to submit paper attachments, documents must be delivered to local branches of the National Taxation Bureau by **October 12, 2026**.([mof.gov.tw](https://www.mof.gov.tw/Eng/singlehtml/f48d641f159a4866b1d31c0916fbcc71?cntId=61ab0bb237564e1ca593dea59501b1d9&utm_source=openai))
## Practical Steps for Compliance & Planning
1. **Mark your calendar**:
- E-filing portal opens August 15 for returns and payment service.
- Provisional tax period: September 1-30.
- Paper-based supporting docs deadline: October 12.
2. **Prepare documentation in advance**:
- CPA reports, investment tax credits, and certified statements stamped under signature must be digitised (PDF).
- Identify all deductions and credits you may claim under Provisional Income Tax rules.
3. **Ensure digital readiness**:
- Access to secure e-auth methods needed (e.g., MOF Portal certificates).
- Confirm that you and your business information (tax ID, branch, fiscal year) are correct in the tax bureau’s system.
4. **Avoid last-minute issues**:
- File early—upload before September 30 to avoid system downtime.
- Double-check that PDFs are legible and properly stamped/sealed.
- If paper docs needed, use reliable courier or local branch drop-off well ahead of October 12.
## Examples & Calculations
- Enterprise A with standard fiscal year ending December 31 prepares provisional return in September, submits everything via e-filing by September 30.
- Enterprise B uses fiscal year ending April 30 (special fiscal year): needs to check if relief or exemption applies—this rule excludes special fiscal years from the standard filing timeline.
## Strategic Advice
- **Cash-flow planning**: provisional tax payment in advance may require setting aside funds; early filing avoids surprises.
- **Credit maximisation**: ensure investment tax credits are claimed timely and properly evidenced.
- **Audit readiness**: maintain accurate books, have CPA reports ready; if online submission is compromised, fallback is paper by October 12.
- **Stay updated**: MOF may issue clarifications or guides ahead of September. Watch MOF notification channels.
For profit-seeking enterprises, this provisional filing presents an opportunity to manage tax liability proactively. With proper preparation, required digital infrastructure, and adherence to deadlines, the process can be smooth and cost-efficient.