Quarterly Provisional CIT Payments in Vietnam: 2026 Rules

Companies in Vietnam do not file quarterly provisional corporate income tax (CIT) returns — but if total provisional payments for the four quarters fall below 80% of the CIT payable under the annual finalisation, the company faces late-payment interest of 0.03% per day on the shortfall. This is the central risk many accountants and business owners miss: the 80% threshold is measured against the final annual figure — a number the company does not yet know when making Q1 or Q2 payments.

Current rules on quarterly provisional CIT payments

Under Article 24 of Decree 252/2026/ND-CP (guiding the 2025 Law on Tax Administration 108/2025, effective 1 July 2026) and Article 21 of Circular 89/2026/TT-BTC:

No quarterly provisional CIT return is required. The company self-determines the provisional tax for each quarter and pays it to the state budget.
Basis for determining the amount: the quarterly financial statements (if the company is required to prepare them under accounting law) or the quarter’s business results.
Payment deadline for each quarter: no later than the last day of the first month of the following quarter (Clause 2, Article 24 of Decree 252/2026):

Quarter	Payment deadline
Q1	30 April
Q2	31 July
Q3	31 October
Q4	31 January of the following year

A drafting note: before 1 July 2026 the rule read “the 30th day of the first month of the following quarter”; Decree 252/2026 changed it to “the last day of the first month” — in practice this only differs for months with 31 days (July, October, January).

The 80% threshold — the key rule

Point (a), Clause 3, Article 24 of Decree 252/2026: total provisional CIT paid for the four quarters must not be lower than 80% of the CIT payable under the annual finalisation self-declared by the taxpayer.

The critical nuance:

The denominator is the finalised annual tax — a figure only known with certainty at year-end, not the profit plan made at the start of the year.
The numerator is the sum of the four quarterly payments.
A common mistake: “a loss-making quarter means no payment is needed for the whole year” — wrong. The 80% rule compares the four-quarter total against the annual finalisation; companies must estimate the full year from Q1 and adjust progressively, especially in Q3 and Q4 when near-complete data is available.

The underpayment risk: 0.03% per day

If the four-quarter provisional total is below 80% of the finalised annual tax, the company must pay late-payment interest of 0.03% per day on the shortfall (Point (b), Clause 3, Article 24 of Decree 252/2026; the 0.03% daily rate is set in Clause 2, Article 16 of the 2025 Law on Tax Administration 108/2025).

Two technical points:

Late-payment interest runs from the day immediately after the Q4 provisional payment deadline — not separately from each quarter in shortfall — but it applies to the entire shortfall against the 80% threshold.
Example: if the annual finalisation shows VND 1 billion payable but the four quarters totalled only VND 700 million (70%, a VND 100 million shortfall against the 80% threshold of VND 800 million), late-payment interest of 0.03%/day accrues on VND 100 million from 1 February of the following year (the day after the 31 January Q4 deadline) until the day before the shortfall is fully paid.

If the tax authority audits after finalisation

When a tax audit or inspection increases the tax payable beyond the amount the company declared in its finalisation, late-payment interest on the additional amount is calculated under Clause 2, Article 26 of Decree 252/2026 — the 80% mechanism does not apply to the audit-discovered increase.

2026 extension of provisional CIT deadlines (Decree 245/2026)

Decree 245/2026/ND-CP (27 June 2026) extends provisional CIT payment deadlines in 2026 for the sectors listed in its Appendix I and for small and micro enterprises:

Provisional CIT for Q2 2026 → extended to 2 November 2026 at the latest;
Provisional CIT for Q3 2026 → extended to 30 December 2026 at the latest.
During the extension period, no late-payment interest accrues on the extended amounts.
If a supplementary declaration filed before the extension expires increases the tax payable, the additional amount is also covered by the extension.

Note: the extension only defers payment — it does not change the 80% threshold at annual finalisation. The decree does not expressly state whether amounts paid during the extension period count as “provisionally paid” for the 80% test — companies should be cautious and may consult their directly managing tax authority.

Practical recommendations

Overpay rather than underpay. The safe practice is to pay above 80% — even 100% of the estimated annual tax. Overpaid amounts are offset against future tax payable or refunded under the 2025 Law on Tax Administration and Decree 252/2026 (detailed procedures require checking further guidance).
Review estimates at the end of Q3. With nine months of data, the company can estimate the full year with reasonable accuracy — this is the ideal moment to top up any shortfall and avoid late-payment interest running from after the Q4 deadline.
Never understate the finalisation to dodge the 80% rule. Deliberately false declarations to evade tax can trigger tax imposition (ấn định thuế) and penalties under current law — a far bigger risk than 0.03%/day interest.
For newly established companies with fewer than four quarters: how the 80% threshold applies to the first year of operation has not been verified against specific guidance — check further before applying it mechanically.

Frequently asked questions

Must companies file quarterly provisional CIT returns? No. Under Article 21 of Circular 89/2026/TT-BTC, companies only self-determine the provisional amount and pay it to the state budget; no quarterly provisional return is filed.

Q1 was loss-making but Q2 was profitable — is provisional payment required? Yes, based on a full-year estimate. The 80% threshold compares the four-quarter total against the annual finalisation, not each quarter separately. Skipping payment in a loss quarter is normal, but by Q3–Q4 the company must top up so the annual total reaches at least 80%.

What happens to overpaid provisional CIT? In principle, overpaid amounts are offset against tax payable in subsequent periods or refunded under the 2025 Law on Tax Administration 108/2025 and Decree 252/2026. Detailed procedures require checking further current guidance.

Does the Q2/Q3 2026 extension remove the 80% threshold? No. The extension under Decree 245/2026 only defers payment and waives late-payment interest during the extension period; the 80% threshold at annual finalisation still applies.

Sources cited

Decree 252/2026/ND-CP (30 June 2026) guiding the 2025 Law on Tax Administration: Article 24 (quarterly provisional payments), Article 26 (late payment); effective 1 July 2026.
Law on Tax Administration 108/2025/QH15 (10 December 2025): Clause 2, Article 16 (0.03%/day late-payment interest); effective 1 July 2026.
Circular 89/2026/TT-BTC (30 June 2026): Article 21 (no quarterly provisional CIT return required); effective 1 July 2026.
Decree 245/2026/ND-CP (27 June 2026) on 2026 tax payment extensions; effective 27 June 2026 to 30 December 2026.
Note: the former provisional-payment rules (Article 17 of Decree 126/2020, Decree 91/2022, the 2019 Law on Tax Administration 38/2019) have expired and no longer apply.

Need a review of your company’s CIT obligations? The FLAT Law Firm team advises companies on tax compliance, reviews provisional-payment and finalisation risks, and accompanies clients in dealings with the tax authorities. Contact us via our Contact page.

The information in this article is for general reference only, based on the law in force at the time of writing (14 October 2026), and is not legal advice for any specific matter.

Transparency notice: This article was produced by FLAT Law Firm’s AI content production system and has passed the AI Legal Council’s internal quality review; it has not been reviewed by a human lawyer.