Annual corporate income tax (CIT) finalisation is the filing that closes the tax period: the enterprise self-determines its full-year taxable income, reconciles quarterly provisional payments, and pays the shortfall (or handles the excess). For FDI enterprises, this is also when project-specific matters must surface on the return: project tax incentives, loss carryforwards and related-party transactions with the parent. This article sets out the deadline, the dossier set and late-filing sanctions under the current framework.
The deadline: the last day of the third month
Under the Law on Tax Administration 108/2025/QH15 (inheriting the mechanism of the 2019 Law on Tax Administration), the annual tax finalisation dossier must be filed no later than the last day of the 3rd month from the end of the fiscal year (calendar year or a registered fiscal year). For example, an enterprise whose fiscal year equals the calendar year must finalise 2026 by 31 March 2027; one with a fiscal year ending 30 June faces a 30 September deadline. During the year, the enterprise provisionally pays CIT quarterly (due on the 30th of the first month of the following quarter), and total provisional payments for the four quarters must reach at least 80% of the finalised liability — any shortfall against the 80% mark accrues late payment interest from the Q4 provisional deadline. CIT substance is determined under the Corporate Income Tax Law 67/2025/QH15 (effective 1 October 2025, applying from the 2025 tax period) and guiding Decree 320/2025/ND-CP.
What does the finalisation dossier contain?
- The CIT finalisation return, form 03/TNDN (issued with Circular 80/2021/TT-BTC on tax filing dossiers) — the central document on which the enterprise self-determines revenue, deductible expenses, taxable income, incentives and the remaining tax payable.
- Appendix 03-1A/TNDN on business results (plus sector appendices for special activities such as real estate or capital transfers).
- Appendix 03-2A/TNDN on loss carryforward if the enterprise carries losses from prior years or incurs a loss this year (see topic FDI-LC-2044).
- Appendix 03-3A/TNDN on CIT incentives if the project is enjoying incentives (see topic FDI-LC-2043).
- The audited annual financial statements — FDI enterprises are under mandatory audit, so the attached statements carry an audit opinion.
- The related-party transaction appendices under Decree 255/2026/ND-CP if the enterprise has related-party relationships and transactions in the period (see topic FDI-LC-2048).
Late filing and underpayment: two sanction layers
Sanctions come in two independent layers. The procedural layer — filing late: administrative fines under Article 13 of Decree 125/2020/ND-CP on a time scale (warning for 1–5 days late with mitigating circumstances; monetary fines rising through the 6–30, 31–60 and 61–90 day bands and over 90 days, with the top bracket at VND 15–25 million). The tax layer — underpaying or paying late: late payment interest of 0.03% per day on the late amount, from the deadline to the actual payment date; where an incorrect declaration causes a tax shortfall, the fine is 20% of the under-declared tax (Article 16 of Decree 125/2020/ND-CP), and much higher for tax evasion. The layers accumulate: a dossier filed 100 days late with a tax shortfall bears both the procedural fine and interest on the tax.
Frequently asked questions
When is the CIT finalisation deadline?
No later than the last day of the 3rd month after the fiscal year ends, under the Law on Tax Administration 108/2025/QH15. For a calendar-year enterprise, the 2026 finalisation is due 31 March 2027. Provisional payments over the four quarters must reach at least 80% of the finalised amount, or the shortfall bears late payment interest.
What does the CIT finalisation dossier include?
Return form 03/TNDN; appendix 03-1A (business results), appendix 03-2A (loss carryforward) if any, appendix 03-3A (incentives) if any; the audited annual financial statements (audit is mandatory for FDI); and the related-party appendices under Decree 255/2026/ND-CP if there were related-party transactions in the period.
How much is the fine for late finalisation?
Two layers: a procedural late-filing fine under Article 13 of Decree 125/2020/ND-CP on a lateness scale (top bracket VND 15–25 million beyond 90 days), plus 0.03% per day late payment interest on the tax shortfall and a 20% fine on under-declared tax where the declaration was incorrect.
Can the CIT finalisation deadline be extended?
Yes, but only in force majeure events (natural disaster, fire, epidemic, unexpected incidents) under the Law on Tax Administration: the enterprise files a written extension request before the deadline, and the extension is capped at 60 days for annual finalisation dossiers. Ordinary financial difficulty is not a ground for extension.
This article has been quality-reviewed by the FLAW AI Legal Council