Filling in information on related party relationships and transactions is a mandatory task that any business with related party transactions must complete concurrently with the corporate income tax return, starting from the 2026 tax year. Decree 255/2026/ND-CP Officially in effect. Even a single incorrect entry in the related party's name, tax identification number, or type of related party relationship is enough to render the entire appendix incomplete, risking a reassessment of tax obligations. This article systematizes the legal basis and how to fill in related party and related-party transaction information according to the appendix structure issued with Decree 255/2026/ND-CP.
Why will filling out information on related party relationships and related-party transactions become a mandatory requirement starting from the 2026 fiscal year?
Filling in information on related-party relationships and related-party transactions means that businesses must fully and accurately declare all related parties, the form of relationship, and the transactions arising with those parties in the appendix attached to the corporate income tax return. This is not merely an administrative procedure, but the first basis for the tax authorities to determine whether the business falls within the scope of regulations on related-party transaction pricing and limits on interest expense deductions.
Decree 255/2026/ND-CP on tax management for enterprises with related-party transactions replaces Decree 132/2020/ND-CP and Decree 20/2025/ND-CP, taking effect from July 1, 2026, and applying immediately from the corporate income tax period of 2026. The method of identifying related-party relationships under Article 5 of this Decree is clarified and expanded compared to before, resulting in a broader scope of enterprises required to declare related-party relationships and related-party transactions in 2026, including those that previously claimed to have no related-party transactions. Specific changes regarding the exemption threshold for filing, the priority order of comparative data, and the standard for reporting country-by-country profits have been analyzed in detail in this article. New points of Decree 255/2026/ND-CP, Businesses should cross-check these documents when preparing their applications.
Omitting or incorrectly filling in information about related party relationships and related-party transactions leads to three direct consequences:
- The appendix was deemed incomplete, so the related-party transaction pricing documentation was also questioned.;
- The tax authorities have grounds to reassess taxable income if they discover undeclared related-party relationships.;
- And businesses lose the opportunity to prove they are exempt from preparing price determination documents if they meet the conditions but fail to provide supporting data.
Legal basis and scope for filling in information on related party relationships and related party transactions.
Tax period and general taxpayer information
Before delving into the core content, filling out the related party relationship and transaction information begins with two pieces of background information:
- Tax period: Record the information corresponding to the tax period of the corporate income tax return, as determined by the Corporate Income Tax Law. Businesses whose tax periods do not coincide with the calendar year need to pay special attention to recording the correct period to avoid discrepancies with the main tax return.
- General taxpayer information: From item [01] to item [09], record consistently with the information declared in the corporate income tax return.
The overarching principle: All general information when filling out the related party and related party transaction information must absolutely match the corporate income tax return for the same period, even if the two documents are prepared by two different departments within the enterprise.
Who is required to provide information on related party relationships and related-party transactions?
The obligation to declare related-party relationships and related-party transactions only applies to taxpayers who have related-party transactions during the period, as defined in Article 5 of Decree 255/2026/ND-CP. The most common criteria that businesses need to review before concluding whether they are required to declare include:
- Ownership relationships of capital from 25% onwards, directly or indirectly, between the parties.
- The relationship arises from guarantees or loans of any kind when the loan amount simultaneously reaches two thresholds: at least 25% of the owner's equity of the borrowing enterprise and over 50% of the total value of the borrowing enterprise's medium and long-term debts.
- Relationships arising from loan, lending, borrowing, or lending transactions with individuals who manage or control businesses, or individuals with whom they have a family relationship as stipulated by regulations.
See also: Identify the 12 types of linkages according to Decree 255/2026/ND-CP.
Important note: If a credit institution or other organization provides a loan but does not participate in the management, control, capital contribution, or investment of the borrowing or guaranteeing enterprise, then that loan alone does not create an affiliated relationship. For enterprises borrowing purely from commercial banks, if they can prove this condition, they may not need to fill in the information on affiliated relationships and related-party transactions for that specific loan, but they must retain supporting documentation; this information cannot be assumed.
Detailed instructions on how to fill in information on related party relationships and related-party transactions can be found in Section I.
The key part when filling out information on related-party relationships and transactions lies in Section I – Information about related parties. This is a detailed list of each related party with which the business has transactions during the period, consisting of four main column groups.
Link name column: Enter the correct subject type.
Column (2) requires the full name of each affiliate, but the recording method is divided into two cases:
- If the affiliated party in Vietnam is an organization: Record the information as stated in the business registration certificate; if it is an individual, record the information as stated in their citizen identification card, passport, or other personal identification document.
- If the related party is an organization or individual outside Vietnam: Record the information as it appears in the document identifying the related party, such as a business registration certificate, contract, or transaction agreement between the taxpayer and the related party.
The most common discrepancy in this column is the use of abbreviations or trade names instead of the full legal name on the license, which causes discrepancies when cross-referencing records by tax authorities during business registration data searches.
Column representing country and territory of residence
Column (3) records the name of the country or territory where the affiliated party is a tax resident. For multinational corporations with ownership structures through multiple layers of intermediate legal entities, the enterprise needs to correctly identify the tax residence of the legal entity directly involved in the transaction, not the location of the final parent corporation's headquarters.
Tax identification number column for affiliated companies
Column (4) is the column most likely to be left blank when filling in information on related party relationships and related party transactions with foreign related parties:
- Affiliates that are organizations or individuals in Vietnam: Please provide the full tax identification number.
- For affiliated parties that are organizations or individuals outside Vietnam: Enter the tax identification number or taxpayer identification number in their country of origin; if none is available, state the reason instead of leaving it blank.
Note: If "none" and "blank" are two different states on a tax return. A blank space without explanation can easily be misinterpreted as incomplete declaration, while a space clearly stating the reason for the absence of a tax identification number indicates that the business has thoroughly reviewed its records.
Column for the form of relationship: Mark correctly and completely according to Clause 2, Article 5.
Column (5) is the hinge part of Section I: based on Clause 2, Article 5 of Decree 255/2026/ND-CP, the enterprise marks “x” in the form of association relationship corresponding to each affiliated party.
If a related party simultaneously belongs to multiple forms of relationship, for example, both owning capital on 25% and acting as a guarantor for a loan, the business must check all corresponding boxes, not just select the "primary" form.
This is the error that causes many applications to be requested for further clarification: Businesses only mark the ownership relationship while omitting the relationship arising from loan guarantees, even though both exist simultaneously with the same partner. Filling in information on related-party relationships and related-party transactions requires businesses to review all loan agreements, guarantee letters, ownership structures, and borrowing and lending transactions with individual executives before marking them, instead of just listing the most obvious form of association.
Relevant information to be cross-referenced when completing the related-party transaction documentation.
Accurately filling in information on related-party relationships and related-party transactions is a necessary condition. For the documentation to stand up to audit, businesses not exempt from the requirement to prepare it must also compare the declared data with the pricing methods and comparative analysis applied in the related-party transaction pricing documentation.
Expand the scope of analysis and comparison according to Article 9.
Given the unique nature of related-party transactions, where no independent comparable entity can be found within the same market, Article 9 of Decree 255/2026/ND-CP allows for an expanded scope of analysis and comparison by industry, geographical market, and comparison timeframe.
Specifically, businesses can first select independent comparable entities based on the most similar statistical economic sectors within the same geographical area or locality in the country, and then expand to countries in the region with similar industry conditions and levels of economic development.
When expanding this scope, businesses must analyze qualitative and quantitative similarities and material differences as prescribed in Clause 6 of Article 10 and Article 14 of the Decree, or adjust for differences due to time factors if using data from the previous fiscal year; the extended period for collecting comparative data shall not exceed one fiscal year compared to the taxpayer's fiscal year.
Profit allocation principles as per Article 15
For complex related-party transactions arising within a chain of transactions involving multiple parties, Clause 2 of Article 15 of Decree 255/2026/ND-CP stipulates that the profit allocation method is the method of allocating the total profit earned to determine the profit of the taxpayer participating in that chain of transactions.
This method is only applicable when the total actual profit and potential profit are determined by financial data based on reasonable and valid documentation, and the value and profit of the transaction must be determined using the same accounting method throughout the application period.
These two points are not directly included in the appendix for filling in information on related-party relationships and related-party transactions, but they determine the persuasiveness of the entire accompanying transfer pricing documentation.
For cases with complex transaction structures or multiple layers of related parties, businesses should consider using related party transaction documentation service To ensure that the comparative analysis and profit allocation match the data declared in Section I.
5 common mistakes when filling out information about related party relationships and related-party transactions.
Firstly, the affiliated party's name is recorded using its trade name instead of its legal name. This results in discrepancies between the records and the business registration data or documents identifying the affiliated relationship when the tax authorities conduct a review.
Second, leaving the tax identification number of the foreign affiliated entity blank instead of clearly stating the reason for its absence is the most common technical error, causing the appendix to be considered incomplete even though the business did not intentionally conceal information.
Third, only marking one form of affiliated relationship even if that party belongs to multiple forms. For example, omitting a loan guarantee relationship when the affiliated party has already been marked as having a capital ownership relationship reduces the accuracy of the overall picture of affiliated relationships.
Fourth, by default, bank loans are assumed to have no related-party relationship without supporting documentation. The exception for independent credit institutions is a conditional exception, requiring proof that the lender is not involved in management, control, capital contribution, or investment—it cannot be inferred when filling out information on related-party relationships and related-party transactions.
Five, the general information of the taxpayer does not match the corporate income tax return for the same period. Even small discrepancies in indicators [01] – [09] create the first point of suspicion when the file is cross-checked.
This 5-step process helps you accurately fill in related party relationship and transaction information right from the start.
Here are 5 steps to help you accurately fill in related party relationship and transaction information:
- Step 1 – Review all relationships according to Article 5: Compile ownership structure, loan agreements, guarantee letters, borrowing or lending transactions with the managing individual to create a complete list of related parties during the period.
- Step 2 – Standardize the identifying information of each affiliated party: Compare the legal name, tax country of residence, and tax identification number of each party with the original documents (business registration certificate, contract, transaction agreement).
- Step 3 – Identify the full form of affiliation for each party: Refer to Clause 2 of Article 5 to correctly and completely mark the corresponding boxes, ensuring that no case of a party belonging to multiple forms of affiliation is omitted.
- Step 4 – Compare the declared data with the transfer pricing documentation: Ensure that the comparison and profit allocation methods applied in the documentation are consistent with the declared list of related parties and transactions.
- Step 5 – Cross-check with the corporate income tax return. Recheck all general taxpayer information and related financial data before submitting it with the tax return documents.
Conclude
Filling in information on related party relationships and related-party transactions according to Decree 255/2026/ND-CP is not just about filling in an appendix attached to the corporate income tax return, but is a step in establishing the data foundation for all tax obligations related to related-party transactions during the period.
Three points to remember:
- The identifying information for each affiliated party must be legally accurate and complete, depending on the specific circumstances, whether domestic or international.;
- The type of relationship must be adequately marked when a party meets multiple criteria simultaneously;
- And all declared data must be consistent with the accompanying transfer pricing documentation.
If your business is still unsure about identifying related parties, classifying the type of relationship, or comparing data with pricing records, our team of experts can assist you. related party transaction advisory services At MAN – Master Accountant Network, we are ready to review documents with your company before they are submitted. A thorough review before the deadline is always easier than having to explain things after an audit.
Contact MAN – Master Accountant Network For free support and advice!
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Responsible for production and professional content review by: Mr. Le Hoang Tuyen – Founder & CEO of MAN – Master Accountant Network. He is a CPA Vietnam auditor with over 30 years of in-depth experience in accounting, auditing, taxation, and corporate legal consulting.
Frequently Asked Questions about filling out related party and transaction information
If a business does not have any related-party transactions during the period, is it still required to fill in information on related-party relationships and related-party transactions?
No. This obligation only applies to taxpayers who are related parties and have related-party transactions during the period, as stipulated in Article 5 of Decree 255/2026/ND-CP.
How should I record the information if the foreign affiliated company does not have a tax identification number?
Enter the tax identification number or taxpayer identification number in the country of residence; if none is available, state the reason instead of leaving this box blank.
When applying for a loan from a commercial bank, is it always necessary to fill in information about related-party relationships and related-party transactions?
Not necessarily. If the lending institution does not participate in the management, control, capital contribution, or investment in the borrowing or guaranteeing enterprise, then that loan alone does not create an affiliated relationship.
Does the taxpayer's general information when filling out the appendix need to match the information on the corporate income tax return?
Yes. Indicators [01] to [09] must be recorded consistently with the information declared in the corporate income tax return for the same period.
From which tax period does Decree 255/2026/ND-CP apply?
The Decree takes effect from July 1, 2026 and applies from the corporate income tax period of 2026, replacing Decree 132/2020/ND-CP and Decree 20/2025/ND-CP.