Accrual of Inheritance Tax in holographic wills: Supreme Court doctrine (STS 356/2026, 2 February)

The Supreme Court, Administrative Chamber, has issued judgment no. 88/2026, of 2 February (appeal in cassation 6890/2023), in which it addresses the timing of the accrual of Inheritance and Gift Tax (IGT) where the designation of heir derives from a holographic will.

The ruling dismisses the appeal lodged by the Community of Madrid and upholds the judgment of the High Court of Justice of Madrid, which had annulled a tax assessment on the grounds that the Administration’s right to determine the tax liability was time-barred.

The case raised an issue of cassational interest as it directly affected the determination of the dies a quo of the tax accrual and, consequently, the starting point for the computation of the relevant tax limitation periods.

The dispute focused on whether, in cases involving holographic wills, the accrual of IGT should be set at the date of the deceased’s death or at the later moment of formalization (protocolization) of the will.

The regional tax authority argued that, pursuant to Article 689 of the Spanish Civil Code, a holographic will does not produce legal effects until it has been verified and formalized, and therefore the inheritance could not be considered acquired prior to that moment.

Under this reasoning, the accrual of the tax would be deferred, along with the starting point of the limitation period for the Administration’s right to assess.

By contrast, the High Court of Justice of Madrid held that the accrual must be fixed at the date of death, and that the lack of formalization does not interrupt or suspend the relevant time limits, thus concluding that the Administration’s right to assess was time-barred.

The Supreme Court resolves the issue through a systematic interpretation of Article 24 of the Inheritance and Gift Tax Act, Articles 47 and 69 of its Regulations, Article 689 of the Civil Code, and Article 67.1 of the General Tax Law.

The Court starts from the general rule set out in Article 24.1 of the IGT Act, according to which the tax accrues on the date of the deceased’s death, and examines whether the formalization of a holographic will may alter this rule for tax purposes.

In this analysis, the Court concludes that, in the case examined, such formalization cannot be regarded as a suspensive condition within the meaning of Article 24.3 of the Act, but rather as a formal requirement of civil law which does not shift the moment of accrual.

The judgment places particular emphasis on the nature of the formalization procedure, classifying it as a matter of voluntary jurisdiction, characterized by the absence of dispute.

In this regard, Article 69.5 of the IGT Regulations provides that proceedings of voluntary jurisdiction which are non-contentious do not suspend tax deadlines, which is decisive for determining the starting point of the time limits.

On this basis, the Supreme Court establishes that, in the cases examined, the accrual of IGT occurs at the date of death. From that moment, the six-month period for filing the tax return begins, followed—once expired—by the four-year limitation period provided under the General Tax Law.

Applying this doctrine to the specific case, the Court concludes that the Administration’s right to assess the tax had already expired, as no valid interruption of the limitation period had occurred, thereby confirming the annulment of the assessment.

The ruling expressly refers to Supreme Court judgment 58/2026, of 27 January, thereby consolidating a uniform interpretative approach regarding the accrual of IGT in cases involving holographic wills.

The judgment does not introduce a new rule, but rather reaffirms the application of the general principle that accrual occurs at the time of death, while clarifying the role of formalization for tax purposes and its impact on the computation of limitation periods under the applicable legal framework.

From the perspective of inheritance taxation, the judgment provides clarity in a particularly sensitive area, where the timing of civil law effects does not always coincide with their tax treatment. This clarification is especially relevant in situations where the existence or effectiveness of a will is established after the death of the testator.

In this context, correctly identifying the moment of accrual and the commencement of the relevant tax deadlines becomes crucial in order to avoid contingencies, particularly in audit or regularization procedures. It is precisely in such scenarios that technical analysis in the field of Inheritance and Gift Tax—such as that carried out at ILIA ETL GLOBAL—enables a rigorous approach to the interaction between civil and tax law, providing legal certainty in the management of complex estates.