Chaos because of "one person, two codes
The 2025 personal income tax (PIT) finalization season is approaching, and many business accountants and employees are facing "laughing and crying" situations related to system data.
Reflecting to functional agencies, Ms. D.T.T (an employee of a business in Hung Yen) said that she is facing major troubles with family deduction dossiers. Specifically, in 2022, she registered her dependent as her biological father and was issued a dependent tax code (MST). However, by 2023, her father had a non-agricultural land tax obligation. At this time, instead of using the old dependent code to pay taxes, the system issued him a new personal MST based on the Citizen Identification Card (CCCD).
The consequence is that currently, Ms. T's father has two codes in parallel on the system. "Because personal papers cannot be synchronized to update into the dependent's tax code, the company cannot finalize. If the old code is closed and the new code is used, will the previous year's finalization declarations that have been declared have to be redone?" - Ms. T worried.
Personal identification number is the only "key
To solve this problem, representatives of the Hung Yen Provincial Tax Department have issued specific guidance based on the Law on Tax Administration No. 38/2019/QH14 and especially Circular No. 86/2024/TT-BTC (new regulations on tax registration).
According to the principle of immutable: Each individual is only granted 01 unique tax code for lifetime use. The tax code issued to dependents is also the personal tax code of that person when obligations to the state budget arise (such as paying land tax, business tax...).
Notably, from July 1, 2025, the Tax sector officially switched to using the Personal Identification Number (number on the chip-attached CCCD card) instead of the traditional tax code.
Therefore, in the case of being issued 2 duplicate codes like Ms. T's father, the tax authority guides the handling process as follows:
Data update: Individuals must update personal identification number (CCCD) information for all tax codes that have been issued. The tax system will base on this identification number to integrate and consolidate data into one connection.
Code conversion: If it cannot be updated due to system errors, individuals carry out procedures to transfer "Dependent Tax Number" to "Tax Payer Tax Number", then update CCCD into this code.
Cancellation of surplus tax code: In case of force majeure, individuals can request the termination of the validity of the surplus tax code.
No need to adjust old tax records
An important piece of information to help relieve the biggest concerns of businesses and taxpayers is the inheritance of data.
Based on Clause 4, Article 39 of Circular No. 86/2024/TT-BTC, the tax authority affirms: "When the tax code has been integrated into the personal identification number, the invoices, documents, and tax records that have used old tax code information will continue to be used to carry out administrative procedures".
Simply put: Businesses and employees do not have to adjust information on tax finalization declarations, invoices, and documents of previous years (2022, 2023...) to personal identification numbers. Old dossiers still retain their legal value.
This helps businesses minimize administrative procedures, avoiding having to declare and supplement a series of past records just because of the change in the current management code.
