Hearing that a tax inspection is coming, many companies rush to “fix” their books — usually too late. The wiser approach: hire an independent firm to review your tax obligations in advance, find errors, and voluntarily correct them in time. A clarification up front: the law does not require companies to undergo a “tax audit” — this is a voluntary service (“audit of financial statements for tax purposes” and tax consulting under Article 40 of the Law on Independent Audit 67/2011/QH12). This article covers three core benefits, four golden moments, and a checklist for choosing a provider.
Table of contents
- Concept check: there is no mandatory “tax audit”
- Benefit 1 — the “penalty-free window” for timely voluntary correction
- Benefit 2 — the supplementary filing window is now 5 years: review early, fix early
- Benefit 3 — proactive defense when inspectors arrive
- Cost comparison: fixing it yourself first vs. being caught
- Four golden moments to hire a tax review
- What a tax review should cover
- Checklist for choosing a review firm
- Frequently asked questions
- Sources
1. Concept check: there is no mandatory “tax audit”
Vietnamese law does not define “tax audit” as a distinct service type or a mandatory audit. What the law does provide:
- Article 40, Law on Independent Audit 67/2011/QH12: audit services include “audit of financial statements for tax purposes” (Article 40.1(a)); audit firms may register to provide “economic, financial and tax consulting” (Article 40.2(a));
- Mandatory financial-statement audits (Articles 9 and 37, Law 67/2011) opine on whether financial statements are true and fair under accounting standards — they do not substitute for a review of tax obligations.
What companies actually need is a “tax obligation review” — performed by an audit firm or tax agent under contract: re-examining all declared tax obligations, identifying errors, and proposing remedies before the tax authority steps in.
2. Benefit 1 — the “penalty-free window” for timely voluntary correction
This is the benefit with the clearest legal footing. Under Article 9.3 of Decree 125/2020/ND-CP (administrative penalties for tax and invoice violations), as amended by Article 1.7 of Decree 310/2025/ND-CP (02/12/2025):
No administrative tax penalty applies where the taxpayer filed incorrectly but has filed a supplementary return and voluntarily paid the full tax due before the tax authority announces its tax examination decision, or before a competent authority announces an inspection decision at the taxpayer’s premises, or before the authority discovers the issue other than through an on-site examination.
In other words: find errors through an independent review → file corrections + pay the shortfall + late-payment interest before the inspection decision is announced → pay only the tax and interest, with no administrative penalty. That is the “penalty-free window” no company should miss — and the core reason to review before, not after, an inspection decision.
3. Benefit 2 — the supplementary filing window is now 5 years: review early, fix early
Under Article 12.5 of the Tax Administration Law 108/2025/QH15 (effective 01/7/2026), taxpayers may file supplementary returns for erroneous filings within 05 years from the filing deadline of the tax period containing the error — provided this happens before the tax authority or a competent authority announces an inspection decision.
Compared with the 10-year window under the old Law 38/2019/QH14, this window has been halved. The practical consequence: errors in older tax periods “close” faster — the longer a company delays its review, the greater the risk of discovering errors only after the correction window has shut. Reviewing early and fixing early avoids not just penalties but also back-tax, late-payment interest and tax assessment.
4. Benefit 3 — proactive defense when inspectors arrive
A serious independent review gives the company a complete “defense file”: risk items identified, errors corrected with vouchers, sensitive expenses documented for explanation. When the inspection team arrives, the company negotiates from strength rather than reacting.
The law also grants taxpayers significant rights during tax examinations (Article 37.1, Law 108/2025), including: contracting a tax agent for agency services; refusing an examination without a decision/notice; refusing to provide information unrelated to the examination’s scope; explaining, reserving opinions in the minutes; and complaining or suing as prescribed. Understanding and preparing to exercise these rights in advance helps the company lawfully protect itself throughout the process.
5. Cost comparison: fixing it yourself first vs. being caught
- Scenario A — independent review + timely voluntary correction: the review fee + the underpaid tax + late-payment interest. No administrative penalty (Article 9.3, Decree 125/2020 as amended by Decree 310/2025);
- Scenario B — caught by the authority during inspection: the underpaid tax + late-payment interest + a 20% penalty on the shortfall; if deemed tax evasion, penalties reach 1–3 times the evaded tax — plus the risk of tax assessment and criminal liability in serious cases.
The gap between the two scenarios is typically many times the review fee. Bluntly: an independent review fee is the cheapest “insurance” in tax risk management.
6. Four golden moments to hire a tax review
- Year-end, before finalization season: one review round before “closing the books” on CIT and PIT finalization — the most cost-effective timing;
- When an inspection looks likely: companies in high-risk industries, with sudden revenue spikes, or just examined on-site with issues found;
- After restructuring, M&A, or major intra-group related-party transactions: these are the authority’s focal points under Decree 255/2026/ND-CP on tax administration for enterprises with related-party relationships;
- When changing the chief accountant or accounting system: “new people, new system” is when old errors are most easily missed — and when an independent eye is most needed.
7. What a tax review should cover
- Deductible vs. non-deductible expenses for CIT: voucher-less spending, over-limit expenses, costs unrelated to business operations;
- Risky invoices: invoices from absconded or dissolved issuers; invalid or unlawful invoices;
- Related-party obligations: Appendix I filings, transfer pricing documentation;
- Foreign contractor tax on payments to overseas partners;
- Tax incentives currently enjoyed: whether eligibility conditions still hold and supporting dossiers remain complete.
8. Checklist for choosing a review firm
- Is a licensed audit firm holding a certificate of eligibility to provide audit services, or a qualified tax agent;
- Is independent of the company (not the firm’s regular bookkeeping provider — avoid “playing and refereeing”);
- Has practical experience with comparable industries and company sizes;
- Commits to confidentiality in writing in the service contract;
- Delivers a report that names each error, its legal basis and the remedy — not just generic opinions.
9. Frequently asked questions
Does the law require companies to undergo a tax audit?
No. The law provides no mandatory “tax audit”. Companies may voluntarily engage an audit firm for an “audit of financial statements for tax purposes” or for tax consulting and obligation reviews (Article 40, Law 67/2011).
Is voluntary correction before an inspection decision penalized?
No administrative tax penalty applies if the supplementary return is filed and the full tax voluntarily paid before the examination/inspection decision is announced (Article 9.3, Decree 125/2020 as amended by Article 1.7, Decree 310/2025) — only the tax and late-payment interest are due.
How long is the supplementary filing window?
05 years from the filing deadline of the erroneous tax period (Article 12.5, Law 108/2025) — down from 10 years under the old law. Condition: before the authority announces an inspection decision.
With an audit report, the tax authority won’t inspect us anymore — right?
Wrong. An audit report is only the company’s self-review tool; it does not bind the tax authority and does not discharge the duty to self-declare, self-assess and self-pay. Nobody can promise a “tax audit gets you through inspection 100%”.
How often is a company inspected?
There is no public rule on inspection cycles — that belongs to the tax industry’s internal planning. Companies should review annually rather than wait.
10. Sources
- Law on Independent Audit 67/2011/QH12 (in force): Article 40 (audit of financial statements for tax purposes; tax consulting); Articles 9, 37 (mandatory FS audits);
- Tax Administration Law 108/2025/QH15 — effective 01/7/2026 (replacing Law 38/2019/QH14): Article 12.5 (05-year supplementary filing), Article 37.1 (taxpayer rights; tax agency contracts);
- Decree 125/2020/ND-CP (amended by Decree 310/2025/ND-CP of 02/12/2025 and Decree 291/2026/ND-CP of 21/7/2026): Article 9.3, as amended by Article 1.7 of Decree 310/2025 (no administrative penalty for timely voluntary correction);
- Decree 252/2026/ND-CP — effective 01/7/2026: detailed implementation of Tax Administration Law 108/2025 (declaration, supplementary filing, payment, late-payment interest…);
- Decree 255/2026/ND-CP — effective 01/7/2026: tax administration for enterprises with related-party relationships.
Does your company need an introduction to a qualified independent audit firm or a tax-obligation review before inspection season? Contact FLAT Law Firm for advice.
Disclaimer
This article is for general reference only and does not constitute legal advice for any specific case. It was drafted by AI and quality-checked by the AI Legal Council of FLAT Law Firm; it has not been reviewed or approved by a human lawyer. Regulations may change; please check the current legal texts or consult a lawyer before applying.