What Must Collapse for a Tax Assessment to Collapse with It: An Improper Purpose in a Tax Audit, Taxation Criteria in the Form of Directives, and a Decision of Limited Unconstitutionality on a Delegating Provision

Question

In cases contesting a large-scale tax disposition, it is rare for a taxpayer to contest only an error in the calculation of the tax amount. This is because it is disputed together whether the tax audit that gathered the tax data was lawful and whether the lower-level norm that served as the basis of taxation has force binding the people, and if either axis collapses, the disposition as a whole may be shaken even if the calculation of the tax amount is correct.

This article asks the questions by separating the two axes. On the axis of procedure, it examines what becomes of a tax disposition based on data gathered through a tax audit when the audit has deviated from its inherent purpose of collecting tax data or verifying the accuracy of the contents of a tax return. On the axis of norms, it examines whether a taxation standard in the form of an administrative rule, such as a directive of the Commissioner of the National Tax Service, can serve as a statutory ground for taxation, and what becomes of an Enforcement Decree provision where the higher delegating provision has been the subject of a decision of limited unconstitutionality by the Constitutional Court.

Article 59 of the Constitution of the Republic of Korea provides that the kinds and rates of taxes shall be determined by Act, and Article 75 provides that the President may issue Presidential Decrees on matters delegated by an Act within the scope specifically defined by that Act. The lower the ground for taxation descends, from an Act to a Presidential Decree and then to rules internal to an administrative agency, the more it becomes a question in what capacity that provision binds the taxpayer.

The three judgments were rendered in 1987, 1996, and 2016, and each addresses the statutes and regulations in force at the time. In particular, the two judgments of 1987 and 1996 concern cases contested from different angles over the same Article 170, paragraph (4), subparagraph 2 of the former Enforcement Decree of the Income Tax Act. This article reads the judgments on the basis of the statutes and regulations in force at the time of the conduct, and sets out the current provisions only to the extent that comparison is necessary.

Material to check

On the axis of procedure, the first material to examine is the circumstances surrounding the commencement of the tax audit. The grounds for selecting the audit subject, the reasons and period of the audit stated in the notice of audit, and the internal reports and instruction documents of the tax authority before and after the commencement of the audit show the purpose of the audit. What was placed at issue in Supreme Court Decision 2016Du47659 was the purpose of the audit, so the central materials are those showing why the audit began at that time and against that subject, rather than whether formal requirements were satisfied.

Next, the records of the tax audit process are examined. Current Article 81-2, paragraph (3) of the Framework Act on National Taxes provides that when a tax official begins a tax audit, the official shall present an auditor identification card, deliver a Taxpayer Charter of Rights, and explain the reasons for the audit, the audit period, and the procedures for remedy of rights, among other matters. Whether this procedure was observed is an issue separate from the violation of purpose, but how the reasons for the audit were explained may serve as material for assessing the purpose.

The third is the connection between the collected tax data and the tax disposition. It is organized by material whether the data that served as the basis of the tax disposition came from the tax audit at issue, or was also obtained through a separate lawful route. What the Summary of Decision states is the unlawfulness of a tax disposition based on tax data collected through such a tax audit, and so the source of the data is directly linked to the fate of the disposition.

On the axis of norms, the chain of delegation of the norm underlying the taxation is mapped out. It is recorded step by step what the Act provision delegated to the Presidential Decree, what the Presidential Decree in turn directed which administrative agency to determine, and in what form of provision that administrative agency determined that content. In Supreme Court Decision 86Nu484, the delegation under the Income Tax Act, the granting of the power of designation under the Enforcement Decree, and the enumeration of transaction types in the Regulations on the Handling of Property Tax Affairs, a directive of the Commissioner of the National Tax Service, made up this chain.

The fifth is whether the delegation provision specified the procedure or method of the exercise of authority. Supreme Court Decision 86Nu484 recognized supplementation in the form of a directive on the ground that the Enforcement Decree imposed no restriction whatsoever as to the procedure or method of designation. If the delegation provision requires a particular form, the assessment may differ, so the text of the delegation must be verified against the original.

Finally, the operative part and form of the Constitutional Court decision are verified. Whether the reasoning of Supreme Court Decision 95Nu11405 applies differs depending on whether the decision is a decision of unconstitutionality depriving an Act provision of its effect, or a decision of limited unconstitutionality declaring it unconstitutional only under a particular interpretation. Current Article 47, paragraph (1) of the Constitutional Court Act provides that a decision of unconstitutionality of an Act binds the courts and all other State agencies and local governments, and paragraph (2) provides that an Act provision decided to be unconstitutional loses its effect from the date of the decision.

Possible readings

The first interpretation reads a violation of the purpose of a tax audit as an independent ground for revocation of the tax disposition. Supreme Court Decision 2016Du47659 held that Article 81-4, paragraph (1) of the Framework Act on National Taxes has concrete normative force in itself, and under this reading, even if the tax amount is substantively correct, a disposition based on data collected through an audit conducted for an improper purpose is unlawful.

The second interpretation reads the scope of application of the judgment narrowly, to the extent that proof of a violation of purpose is difficult. Because the Summary of Decision speaks of cases conducted for an improper purpose rather than for its inherent purpose, the view is possible that it is difficult to regard as unlawful at once even cases in which a motive different from the inherent purpose was present together. In that case, what is determined as the principal character of the purpose becomes the center of the dispute.

The third concerns the scope of the material collected through the unlawful audit. Views may differ between the view that only the material arising from the audit at issue is excluded and a disposition based on material obtained through an independent route may be sustained, and the view that once an audit for an improper purpose has been commenced, the entire disposition connected with that audit is unlawful. The Summary of Decision states only that a disposition based on tax data collected through the audit is unlawful, and does not separately address cases in which material from other routes is mixed in.

The fourth concerns taxation standards in the form of a directive. Under Supreme Court Decision 86Nu484, an administrative rule generally has effect only within the administrative organization, but where a statute or decree grants a specific administrative agency the authority to determine specific matters without specifying the procedure or method, it has effect as delegated legislation, combining with the statute or decree within the limits of delegation. There may be a view reading this narrowly as an exception under the principle of legality in taxation, and a view reading it as a method generally permitted in the supplementation of technical matters.

The fifth concerns the effect of a decision of limited unconstitutionality. Supreme Court Decision 95Nu11405 held that the view on statutory interpretation expressed in a decision of limited unconstitutionality cannot have binding force upon the power of interpretation and application of statutes and decrees that is exclusive to the courts. Following this judgment, the effect of the delegating provision, which remains in force in its original wording, and of the corresponding Enforcement Decree provision, is ultimately determined by the Supreme Court, and this stands in direct opposition to the position that the binding force under Article 47, paragraph (1) of the Constitutional Court Act extends to decisions of limited unconstitutionality as well.

The sixth concerns the interpretation of the scope of delegation. Supreme Court Decision 95Nu11405 held that even where the delegation provision did not expressly specify the scope of the matters delegated to the Presidential Decree, an inherent scope or limit of delegation may be recognized, and did not accept an interpretation limiting the delegation to cases favorable to the taxpayer. Views may differ between the view that this is the general method of drawing the scope of delegation from legislative history and purpose, and the view that it is a determination limited to the Enforcement Decree provision in that case.

What the decisions held

Supreme Court Decision 2016Du47659 decided December 15, 2016, while citing then Article 81-4, paragraph (1) of the Framework Act on National Taxes, stated that this provision prescribes objective necessity, minimality, and the prohibition of abuse of authority, among other things, as requirements for the lawfulness of a tax audit, and that "this is intended to carry through the principle of the rule of law in the realm of tax procedure law as well, and it has concrete normative force in itself." It then stated that "if a tax audit was conducted not for its inherent purpose of collecting tax data or verifying the accuracy of the contents of a tax return, but for an improper purpose, this corresponds to a case in which a serious ground of illegality exists in the tax audit, and a tax disposition based on tax data collected through such a tax audit is likewise unlawful." As the reason, it cited the fact that if abuse or misuse is not prevented, it infringes the tranquility of the taxpayer's business activities and private life or property rights, and casts doubt upon the neutrality, public character, and ethicality of the power of taxation. The operative part dismissed the final appeal and imposed the costs of the final appeal on the defendant.

Supreme Court Decision 86Nu484 decided September 29, 1987 stated that although an administrative rule generally has effect only within the administrative organization, an administrative rule of the kind where a statute or decree does not specify the procedure or method of the exercise of authority and grants a specific administrative agency the authority to determine specific matters of the content of the statute or decree "has effect as delegated legislation with external binding force, combining with them so long as it does not exceed the limits of delegation of the relevant statute or decree." It further stated that the enumeration by the Commissioner of the National Tax Service, in Article 72, paragraph (3) of the Regulations on the Handling of Property Tax Affairs, of the types of transactions to which the actual transaction value applies, "even though the above Regulations on the Handling of Property Tax Affairs are in the form of a directive of the Commissioner of the National Tax Service," supplements the content pursuant to the delegation of the Enforcement Decree of the Income Tax Act and generates external effect, so that, unless there are special circumstances such as exceeding the limits of delegation, it constitutes a statutory ground for taxation of capital gains tax based on the actual transaction value. The operative part reversed the judgment of the court below and remanded the case to the Seoul High Court.

Supreme Court Decision 95Nu11405 decided April 9, 1996 held that even where a decision of limited unconstitutionality exists, so long as the wording of the Act provision remains unchanged and continues in force, that decision can only be understood as statutory interpretation, and the power of interpretation and application of statutes and decrees is exclusive to the courts, with the Supreme Court as the highest court. Accordingly, it held that "the Constitutional Court's view on statutory interpretation expressed in a decision of limited unconstitutionality merely states, as a provisional matter, the Constitutional Court's view on the meaning and content of the statute and the scope of its application, and therefore" cannot affect or have binding force upon the power of interpretation and application of the courts. Even where a decision of limited unconstitutionality exists with respect to a delegating provision, it held that so long as the wording continues in force, the Presidential Decree provision enacted in accordance with the purpose of that delegation likewise continues in force, and, without following the interpretation of Constitutional Court Decisions 94Hun-Ba40, 95Hun-Ba13 of limited unconstitutionality decided November 30, 1995 mentioned in the Summary of Decision, it maintained the earlier view that the delegation provision of the former Income Tax Act and Article 170, paragraph (4), subparagraph 2 of the former Enforcement Decree of the Income Tax Act do not violate the principle of legality in taxation and the principle prohibiting blanket delegation. The operative part dismissed all the final appeals.

Practical checklist

Whether the reasons for the commencement of the tax audit remain in documents. Whether those reasons are connected to the collection of tax data or the verification of the contents of a tax return, or whether there are circumstances showing another purpose toward the person subject to the audit. If such circumstances exist, note down what material distinguishes whether they were an incidental motive present alongside the inherent purpose, or an improper purpose that led the audit.

Whether the underlying material of the tax disposition arose only from the audit at issue. Mark by material whether material showing the same fact was also obtained through independent routes such as a tax return, a notification from another agency, or a separate lawful audit, and confirm which material falls within the scope of a tax disposition based on the collected tax data as stated in the Summary of Decision.

Which form the norm underlying the taxation takes among an Act, a Presidential Decree, an Ordinance of the Ministry, a public notice, or a directive. If it is in the form of an administrative rule, verify in turn whether a higher statute or decree granted that administrative agency the authority to determine specific matters, whether it specified the procedure or method of the exercise of authority, and whether the content of the provision lies within the limits of delegation.

Whether there was a Constitutional Court decision on the taxation provision or its delegating provision. If there was, verify whether the operative part was a simple decision of unconstitutionality or a decision of limited unconstitutionality, and whether the wording of the Act changed after the decision, and organize the structure of the dispute on the basis of the wording of the statutes and regulations in force at the time of the conduct that apply to the case.

Glossary

Prohibition of abuse of tax audit authority: Current Article 81-4, paragraph (1) of the Framework Act on National Taxes provides that tax officials shall conduct tax audits within the minimum scope necessary to realize fair and equitable taxation, and shall not abuse the power of audit for other purposes or the like. The current provision states in parentheses that tax offense investigations are included in tax audits, and paragraph (1) bears a notation of amendment as of December 31, 2018, but this parenthetical is absent from the provision as cited in Supreme Court Decision 2016Du47659.

Administrative rule: A provision issued by a superior administrative agency toward a subordinate administrative agency, prescribing guidelines for the handling of business or standards concerning the interpretation and application of statutes and decrees. It is issued under such names as a directive, an instruction, or a public notice, and Supreme Court Decision 86Nu484 regarded it as generally having effect only within the administrative organization.

Statute-supplementing administrative rule: A descriptive expression referring to a provision which, where a statute or decree grants a specific administrative agency the authority to determine specific matters and that agency determines that content in the form of an administrative rule, has external binding force by combining with the statute or decree within the limits of delegation. The Summary of Decision explains this not as the general effect of an administrative rule, but as arising from the effect of the delegated provision of the statute or decree.

Decision of limited unconstitutionality: A decision by which the Constitutional Court, without depriving an Act provision of its effect, sets forth a specific standard of interpretation and declares it unconstitutional only under such an interpretation. Supreme Court Decision 95Nu11405, taking note of the fact that this decision does not alter the wording of the Act, denied its binding force upon the interpretive power of the courts.

Sources and limitations

The provisions were verified against the current texts of Articles 81-2 and 81-4 of the Framework Act on National Taxes, Articles 59, 75, 101, and 103 of the Constitution of the Republic of Korea, and Article 47 of the Constitutional Court Act on the National Law Information Center as of October 16, 2026. Article 81-4 of the Framework Act on National Taxes was retrieved in the version implementing the partially amended Act dated September 29, 2026.

The judgments were addressed only within the scope of the Holdings, Summary of Decision, and operative part of the judgment texts on the National Law Information Center. Because it does not appear in the Summary of Decision what specifically the improper purpose of the tax audit was in Supreme Court Decision 2016Du47659, or for what reason the court below in Supreme Court Decision 86Nu484 revoked the tax disposition, these were not set down.

The texts as they stood at the time of Article 23, paragraph (4) and Article 45, paragraph (1), subparagraph 1 of the former Income Tax Act, Article 170, paragraph (4), subparagraph 2 of the former Enforcement Decree of the Income Tax Act, and Article 72, paragraph (3) of the Regulations on the Handling of Property Tax Affairs, as well as the texts of the Constitutional Court decisions mentioned in the Summary of Decision, were not compared. The content of these provisions was conveyed only within the scope described in the Summary of Decision.

Points left open

The method of proving an improper purpose and the allocation of that burden of proof are not made clear by the Summary of Decision alone. Because the purpose of an audit is formed within the tax authority, it awaits separate determination to what circumstances a taxpayer must present before a violation of purpose is recognized, and to what degree the tax authority must substantiate the inherent purpose.

After current Article 81-4, paragraph (1) states that tax offense investigations are included in tax audits, it remains a question whether the legal principle of Supreme Court Decision 2016Du47659 applies in the same manner to material collected through a tax offense investigation and to the tax disposition based thereon, and further how it connects to the admissibility of that material in criminal proceedings.

The legal principle of Supreme Court Decision 86Nu484 proceeds on the premise of a case where the delegation provision does not specify the procedure or method of the exercise of authority. Where the delegation provision has prescribed a specific form, such as a Presidential Decree or an Ordinance of the Ministry, this judgment does not directly answer what becomes of the effect of standards prescribed by a directive or a public notice, and where this boundary is drawn in the field of taxation must be read together with other judgments.

Supreme Court Decision 95Nu11405 denied the binding force of a decision of limited unconstitutionality. Because this article did not verify how the effect of a decision of limited unconstitutionality has been handled between the Constitutional Court and the courts since this judgment, or how it connects with retrial or other remedy procedures, this is left as an open issue.

When to reconsider

If the prohibition of abuse of tax audit authority or the restriction on re-investigation under Article 81-4 of the Framework Act on National Taxes, or the audit commencement procedure under Article 81-2, is amended, the reading on the axis of procedure will be compared again. The same applies if the provision on the effect of a decision of unconstitutionality under Article 47 of the Constitutional Court Act changes, or if an express provision on the effect of a decision of limited unconstitutionality is enacted.

If the Supreme Court renders new determinations concerning the violation of the purpose of a tax audit, the external effect of taxation standards in the form of administrative rules, and the effect of a decision of limited unconstitutionality, additions will be made to the item on what the court held within the scope of the Holdings and the Summary of Decision, and the relationship among the three judgments will be described again.

Statutes referred to

• 국세기본법 제81조의2, 제81조의4
• 대한민국헌법 제59조, 제75조, 제101조, 제103조
• 헌법재판소법 제47조

Decisions referred to

• 대법원 2016. 12. 15. 선고 2016두47659 판결 · Decision ledger
• 대법원 1987. 9. 29. 선고 86누484 판결 · Decision ledger
• 대법원 1996. 4. 9. 선고 95누11405 판결 · Decision ledger

Verification status

The cited provisions (Articles 81-2 and 81-4 of the Framework Act on National Taxes, Articles 59, 75, 101, and 103 of the Constitution of the Republic of Korea, and Article 47 of the Constitutional Court Act) were compared against the current texts on the National Law Information Center as of October 16, 2026. The cited judgments (Supreme Court Decision 2016Du47659 decided December 15, 2016, Supreme Court Decision 86Nu484 decided September 29, 1987, and Supreme Court Decision 95Nu11405 decided April 9, 1996) were compared against the Holdings, Summary of Decision, and operative part of the judgment texts on the National Law Information Center. The texts as they stood at the time of the former Income Tax Act, the former Enforcement Decree of the Income Tax Act, and the Regulations on the Handling of Property Tax Affairs were not compared.