Analysis of Legal Provisions 

According to Clause 3, Article 47 of Law No. 38/2019/QH14 on Tax Administration, in cases where the tax authority has issued a conclusion or decision regarding tax matters after an on-site audit, taxpayers are permitted to submit supplemental tax returns under the following cases:

• Increasing the amount of tax payable: When taxpayers discover that they have underreported their tax liability.
• Decreasing the amount of tax deductible: When taxpayers discover that they have claimed excessive tax deductions.
• Decreasing the amount of tax exempt, reduced, or refundable: When taxpayers discover that they have made errors in claiming tax exemptions, reductions, or refunds.
• Administrative penalties for tax violations: For violations specified in Articles 142 and 143 of the Law.

Cases Where Supplemental Tax Returns Are Not Permitted 

If a taxpayer discovers errors in their tax return and submitting a supplemental return would result in:

• Decreasing the amount of tax payable: When taxpayers discover that they have overstated their tax liability.
• Increasing the amount of tax deductible: When taxpayers discover that they have understated their eligible tax deductions.
• Increasing the amount of tax exempt, reduced, or refundable: When taxpayers discover that they have claimed less than the allowable tax benefits. 

In such cases, taxpayers cannot simply submit a supplemental tax return but must follow the procedures for tax dispute resolution.

Determining the Nature of the Error 

To determine the appropriate course of action, the company should carefully assess the nature of the error. Specifically, does the incorrect reporting period and error in item [22] of the supplemental tax return result in an increase or decrease in the amount of tax payable, or does it affect the amount of deductible, exempt, reduced, or refundable taxes?

Course of Action 

• If the supplemental return would result in an increase in the amount of tax payable: The company should proactively prepare a supplemental tax return and submit it to the tax authority. The supplemental return must clearly specify the details of the error and the additional tax due. 
• If the supplemental return would result in a decrease in the amount of tax payable or an increase in the amount of deductible, exempt, reduced, or refundable taxes: The company cannot simply submit a supplemental return but must file a tax appeal. In the appeal, the company must clearly state the grounds for the appeal and provide supporting evidence.

Conclusion 

Submitting a supplemental tax return after a tax audit is a complex process that requires a thorough understanding of tax regulations. To avoid unnecessary risks, businesses should consult accounting experts or lawyers for specific advice in each case.