Corporate income tax (CIT) compliance in Vietnam goes beyond applying the correct tax rate. Businesses operating here face a structured cycle of quarterly payments, an annual finalisation process and detailed procedural requirements that can trigger penalties if mishandled.
This guide covers the practical side of CIT compliance, including what to file and when, how the penalties apply, how to correct the filing errors and what newly incorporated companies need to set up from the start.
- The annual CIT finalisation return is due by the last day of the third month after the fiscal year-end.
- Quarterly provisional CIT payments are required to reach at least 80% of the final annual tax liability or late payment interest will apply to the shortfall.
- Late filing of a tax return can result in administrative fines ranging from VND 2 million to VND 25 million, with a separate daily interest of 0.03% on any unpaid tax.
- Businesses can submit amended declarations within 10 years of the original filing deadline, provided no tax inspection has been announced. From July 2026, this window shortens to five years.
- Newly incorporated companies register for tax, set up their e-invoicing system and make a provisional CIT payment from their first taxable quarter, even if revenues are low.
How the corporate income tax filing works in Vietnam
Vietnam’s CIT system operates on two parallel tracks: quarterly provisional payments and an annual finalisation return. Understanding how these interact is the key to staying compliant.
During the year, businesses estimate their CIT liability and make quarterly provisional payments based on expected profits. At year-end, companies reconcile those payments against the actual tax liability through the annual finalisation, settling any shortfall or carrying forward any excess.
This structure means compliance is continuous. Companies need to track their taxable income position throughout the year to manage the quarterly payment schedule and the 80% threshold rule discussed below.
What to submit for the annual CIT finalisation
The annual CIT finalisation is the most document-intensive part of the compliance cycle. Incomplete or inconsistent submissions are one of the most common reasons for follow-up queries from the tax authority.
The standard filing requirements
The core submission typically includes:
- the CIT finalisation return (Form 03/TNDN under Circular 80/2021/TT-BTC)
- audited financial statements prepared under Vietnamese Accounting Standards (VAS)
- the reconciliation schedule of accounting profit to taxable profit
The reconciliation schedule captures key adjustments such as non-deductible expenses, tax-exempt income and loss carryforwards.
Supporting annexes for tax filing
Depending on the nature of your business, additional annexes may be required. Common annexes include schedules for preferential tax rates or incentives, transfer pricing declarations for related-party transactions and detailed income breakdowns. Incentive claims are closely reviewed; therefore, supporting documentation should be complete and ready at the time of submission. To know more about how financial records are maintained, refer to our guide on bookkeeping and accounting in Vietnam.
Audited financial statements and filing deadline
Foreign-invested enterprises are required to have their annual financial statements audited before submission. The audit is completed by a firm licensed to operate in Vietnam, and the statements align with VAS or International Financial Reporting Standards (IFRS).
The deadline for submitting the annual CIT finalisation is the last day of the third month after the fiscal year-end. For companies using the standard calendar year, this means 31 March. If the company is dissolved, merged or undergoes a change of ownership, a separate finalisation return is required within 45 days of that event.
Quarterly provisional payments and the 80% rule
Quarterly CIT payments are due no later than the 30th day of the first month of the following quarter. For a calendar-year company, this means payments are due on 30 January, 30 April, 30 July and 30 October.
The 80% threshold requirement
Quarterly CIT payments are based on your own estimate of profit, with no prescribed minimum for each individual quarter. However, there is a critical annual threshold: the total provisional payments are equal to at least 80% of the final annual CIT liability determined at year-end.
If this threshold is not met, late payment interest applies to the shortfall from the deadline of the fourth quarterly payment. This often affects companies that underestimate profits and do not adjust the provisional payments during the year. Reviewing your CIT position before the final quarterly deadline in October gives you an opportunity to top up if required.
Penalties for late filings and underpayments
Vietnam’s tax penalty framework, governed by Decree 125/2020/ND-CP, applies different treatments depending on the type of non-compliance.
Key penalty categories for non-compliance
| Type of non-compliance | Penalties |
|---|---|
| Late filing | Administrative fines from VND 2 million to VND 25 million |
| Late payment | Interest at 0.03% per day |
| Understatement of tax | 20% penalty on underpaid tax plus interest |
| Tax evasion | 1 to 3 times the unpaid tax |
Late filing penalties increase with the length of delay and apply per violation. Late payment interest applies separately and accrues from the day after the payment deadline, regardless of whether the return has been filed. A key threshold to be aware of is the 90-day rule. Filing more than 90 days late may be treated as tax evasion rather than an administrative delay, significantly increasing penalties.
If a filing is rejected due to technical errors, it is not considered late, provided it is corrected and resubmitted within the timeframe specified by the tax authority.
How to correct a tax filing error
Errors in tax filings can be corrected, but the process depends on when the error occurred and whether the tax authority has initiated an audit.
Under the current tax administration framework, companies can submit supplementary declarations to correct an error within 10 years from the original filing deadline, provided no inspection or audit decision has been issued. From 1 July 2026, the Law on Tax Administration 108/2025/QH15 shortens this window to five years from the original filing deadline. Companies with potential errors in older filings should review their position before that date.
The correction includes a clear explanation of the error and the revised figures and is submitted through the General Department of Taxation’s e-portal together with an explanatory note outlining the affected period and adjustments made.
Practical implications
If the correction results in additional tax payable, the company pays the outstanding amount along with late payment interest calculated from the original due date. If the correction reduces the tax liability, the company may request a refund or offset the amount against future tax obligations.
The key advantage of voluntary correction is that it typically avoids the higher penalties that apply when errors are identified during a tax audit. However, from 1 July 2026, this distinction narrows: under the new law, supplementary declarations that result in additional tax payable will attract penalties and interest calculated as if the error had been identified during an audit. Filing accurately from the outset becomes more important under the incoming framework.
What are the compliance requirements for newly incorporated companies?
For newly established companies, compliance requirements begin immediately and run alongside operational setup. The requirements include tax registration, fiscal year notification, e-invoicing and, where applicable, VAT registration. They also begin meeting ongoing obligations such as quarterly CIT filings from their first taxable period, regardless of whether tax is payable. Missing early obligations can create complications later. Beyond these compliance requirements, they are also required to address immediate post-registration obligations, as outlined in our post-registration checklist.
Preparation for initial compliance requirements
New companies should ensure that tax registration is completed as it is automatically linked to enterprise registration, and that the fiscal year is formally notified if it differs from the calendar year. An e-invoicing system is also registered and operational before any invoices are issued since it is mandatory in Vietnam, and failure to implement it correctly can result in separate penalties. VAT registration is also required if the annual revenue is expected to exceed the registration threshold.
The first CIT period and provisional payments
The first CIT period can be shorter than a full year, depending on the incorporation date. The law allows flexibility:
- First period can be less than 12 months (up to 15 months maximum)
- Periods under three months may be combined with the following year
Quarterly CIT obligations apply from the first taxable quarter. Even if no tax is payable, companies are still expected to file and track their position.
Tax exemptions for newly incorporated SMEs
From the 2025 tax period, newly registered SMEs benefit from a three-year CIT exemption, starting from the date of ERC issuance, provided the company is registering for the first time and the key persons have not been involved in a dissolved business within the previous 12 months. SMEs converting from registered household businesses receive a separate two-year CIT exemption, which starts from the first year taxable income is generated.
Although these exemptions reduce the tax burden, companies still file returns, maintain proper accounting records and declare exempt income correctly. Failure to follow procedural requirements may affect eligibility for the exemption.
Conclusion
Vietnam’s corporate tax compliance framework is detailed and deadline-driven. The annual CIT finalisation, quarterly payments, the 80% threshold rule and the penalties all require active management throughout the year. These obligations sit within a broader schedule of statutory deadlines outlined in the Vietnam Compliance Calendar 2026. For newly incorporated companies, building the right foundations early makes the ongoing compliance more manageable.
The most important principle is to act before the tax authority does. Correcting errors early, topping up provisional payments before year-end and filing on time help reduce both financial exposure and audit risk. The cost of proactive compliance is less than responding to an assessment.
How Acclime can help with corporate tax compliance in Vietnam
Acclime Vietnam offers end-to-end accounting and tax compliance services, covering quarterly CIT payments, annual finalisation, e-invoice setup and supplementary declarations. Our team works with foreign-invested enterprises from incorporation through ongoing compliance, handling the filings and documentation that tend to create risk when managed without specialist support.
Working with Acclime ensures deadlines are met, reduces exposure to penalties and gives you clear oversight of your compliance position. Contact us to discuss your tax compliance needs and receive the clear steps next.
