Open Decision Ledger · Tax & international taxation
Res judicata and continued existence of interest income in adjustment refusals
Supreme Court, June 25, 2020, 2017Du58991 (judgment)
No holding summary · checked against points at issue. The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Case name: 종합소득세경정거부처분취소
Official text on the National Law Information Center
Question
In a suit to cancel a refusal of a request for tax adjustment, is each ground on which a taxpayer asserts that the tax base and tax amount were unlawfully assessed merely a means of attack and defence, and must the legal evaluation of the relation that gave rise to the taxable income be lawful and valid?
Holding
Yes, on the first point. Because the object of review is the objective existence of the tax base and tax amount, each ground on which the assessment is said to be unlawful is no more than a means of attack and defence. The four taxpayers who had already put the cancellation of the loan contracts to the earlier courts were barred by the res judicata of those final judgments. On the second point, the legal evaluation of the relation that gave rise to the taxable income need not be lawful and valid, so long as the taxpayer economically controls and enjoys the gain; the court below therefore had to examine whether the third plaintiff had returned the interest.
Points at issue, verbatim
감액경정청구에 대한 거부처분 취소소송에서 과세표준 및 세액의 인정이 위법이라고 내세우는 개개의 위법사유는 자기의 청구가 정당하다고 주장하는 공격방어방법에 불과한지 여부
Unofficial English translation
Whether, in an action for revocation of a refusal disposition on a claim for reduced rectification, the individual grounds asserting that the recognition of the tax base and tax amount is unlawful are merely means of attack and defense asserting that one's own claim is well-founded
Disposition
Reversed and remanded Stated in the decision
원심판결을 파기하고, 사건을 서울고등법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Seoul High Court.
Form of the test
Elements stated Stated in the decision
그 심판의 대상은 과세표준신고서에 기재된 과세표준 및 세액의 객관적인 존부라 할 것이므로
Unofficial English translation
the subject matter of that adjudication is the objective existence or non-existence of the tax base and tax amount stated in the tax base return, and therefore
Factors
- 감액경정청구에 대한 거부처분 취소소송에서 과세표준 및 세액의 인정이 위법이라고 내세우는 개개의 위법사유는 자기의 청구가 정당하다고 주장하는 공격방어방법에 불과한지 여부
- 과세소득의 경우 소득을 얻게 된 원인관계에 대한 법률적 평가가 반드시 적법하고 유효한 것이어야 하는지 여부
Unofficial English translation
• Whether, in an action for revocation of a refusal disposition on a claim for reduced rectification, the individual grounds asserting that the recognition of the tax base and tax amount is unlawful are merely means of attack and defense asserting that one's own claim is well-founded
• Whether, in the case of taxable income, the legal characterization of the causal relationship by which the income was acquired must necessarily be lawful and valid
Relation to precedent
Follows earlier decisions Stated in the decision
대법원 2004. 8. 16. 선고 2002두9261 판결(공2004하, 1550)
Unofficial English translation
Supreme Court Decision 2002Du9261 decided August 16, 2004 (Gong 2004 Ha, 1550)
Decisions referred to
[1] 대법원 2004. 8. 16. 선고 2002두9261 판결(공2004하, 1550) / [2] 대법원 1985. 5. 28. 선고 83누123 판결(공1985, 932)
Burden of proof
Not addressed Not in the decision
Open question and revisit condition
Where the taxpayer returned only part of the interest received from the lenders, at what point does the interest income for 2008 to 2010 cease to exist for the purposes of the tax adjustment?
The judgment of the Seoul High Court on remand will show how it decides whether the interest was returned and dismisses the claims on the subject matter point. An amendment to Article 45-2 of the former Framework Act on National Taxes would also call for a fresh reading.
Cross-family AI independent reading & axis check
7 of 8 axes matched GPT-6 Astra (OpenAI, codex CLI) · 2026-10-25
A reader from another model family (GPT-6 Astra), given the official text but not the primary reading, agreed on 7 of the 8 axes; the readings differed on axis 4 (form of the test).
Axis 4 (Form of the test): Primary “Elements stated” vs Independent “Existing test applied”
The standard form differs: the primary reading sets out requirements, while the independent reading applies the standard to the facts of repayment and res judicata.
과세소득의 경우 소득을 얻게 된 원인관계에 대한 법률적 평가가 반드시 적법하고 유효한 것이어야 하는지 여부(소극)Raw responses and comparison record: Protocol · Blind readings (JSONL) · Axis comparison (JSONL) · SHA-256 (JSON)
Lower-court contrast & scope of application
Lower-court reading vs. Supreme Court holding
Lower-court context: The Seoul High Court, in its judgment of 16 August 2017 (2017Nu33413), held that the subject matter of this suit differs from that of the prior final judgments and, on that premise, rejected the tax offices' defence of res judicata. For Plaintiff 3, it held that the exercise of the right to cancel the loan contracts on the lenders' fraud meant the interest income no longer existed, so the refusal was unlawful. It set aside the first-instance judgment dismissing the claims and granted them.
Supreme Court standard: The Supreme Court reversed. Because the object of review is the objective existence of the tax base and tax amount, the subject matter of the prior judgments and of this suit is identical for Plaintiffs 1, 2, 4 and 5, and the cancellation they re-asserted was a means of attack and defence already exercised before the close of argument, so their claims had to be dismissed. For Plaintiff 3, even if the loan contracts had been lawfully cancelled, the interest income for 2008 to 2010 still existed where the plaintiff kept the interest without returning it, so the court below had to find whether it had been returned and failed to do so. Both errors affected the result, and the judgment was reversed and remanded to the Seoul High Court by the unanimous agreement of the Justices.
Distinguishing conditions
- A case in which the taxpayer has returned to the lenders the interest received; the Court held only that the court below had to examine whether the interest was returned before judging whether the refusal was unlawful.
- A case in which the subject matter of the prior final judgment is not the same tax base and tax amount as that of the later suit, since the Court rested on their identity.
- A case in which cancellation of the contract had not been asserted before the close of argument in the prior judgments, since the Court treated it as a means of attack and defence already exercised.
Record verification notes
For each prior tax judgment, fix the date its argument closed and the date the taxpayer asserted cancellation, since the Court treated that assertion as already exercised and so barred. Set the tax years and tax base in the prior judgments against those covered by the refused adjustment. For any plaintiff who cancelled the contracts, gather records showing whether the interest was returned, because the Court held that had to be examined first.
From the official text
Points at issue
[1] 감액경정청구에 대한 거부처분 취소소송에서 과세표준 및 세액의 인정이 위법이라고 내세우는 개개의 위법사유는 자기의 청구가 정당하다고 주장하는 공격방어방법에 불과한지 여부(적극) [2] 과세소득의 경우 소득을 얻게 된 원인관계에 대한 법률적 평가가 반드시 적법하고 유효한 것이어야 하는지 여부(소극)
Unofficial English translation
[1] Whether, in an action for revocation of a refusal disposition on a claim for reduced rectification, the individual grounds asserting that the recognition of the tax base and tax amount is unlawful are merely means of attack and defense asserting that one's own claim is well-founded (affirmative) [2] Whether, in the case of taxable income, the legal characterization of the causal relationship by which the income was acquired must necessarily be lawful and valid (negative)
Summary of the holding
The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Order
원심판결을 파기하고, 사건을 서울고등법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Seoul High Court.
Provisions referred to
[1] 구 국세기본법(2015. 12. 15. 법률 제13552호로 개정되기 전의 것) 제45조의2 [2] 구 국세기본법(2015. 12. 15. 법률 제13552호로 개정되기 전의 것) 제45조의2 제2항 제5호, 구 국세기본법 시행령(2016. 2. 5. 대통령령 제26946호로 개정되기 전의 것) 제25조의2 제2호
Read 2026-10-25 · Cross-read 2026-10-25. All quotes matched against the official text. The Chinese-character placeholders the court used for anonymised parties are given in their Korean readings, and parenthetical Chinese-character glosses are omitted.
Every entry is published only after all quotes have been matched character by character against the official text, and audited by an independent second reading from a different model family across all eight axes. Both agreed axes and text-grounded interpretive divergences are recorded openly. The ledger is a research record, not an assessment of the court or advice on any matter.
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