The right of transmission and chained inheritances: the Supreme Court returns to the double transmission theory

When an heir dies without having accepted or renounced an inheritance to which they were called, their right to accept or reject it does not lapse: it passes to their own heirs. That mechanism, the right of transmission under article 1006 of the Civil Code, governs what in practice we call chained inheritances. The Spanish Supreme Court has just corrected how that transmission operates and has returned to the double transmission theory, with direct effects on who must take part in the partition and on the assessment of Inheritance Tax.

What is the right of transmission under article 1006 of the Civil Code

The right of transmission is the power, granted by law to the heirs of a person who dies without having accepted or renounced an inheritance, to decide on that pending inheritance in their place. Its basis is article 1006 of the Civil Code, under which, upon the death of an heir without accepting or renouncing the inheritance, the same right they held passes to their own heirs.

It is worth fixing the terminology, because everything else depends on it. The first deceased is the person who dies first and leaves the initial estate. The transferor is the heir called to that first inheritance who dies without deciding on it. The transferees are the heirs of the transferor, to whom article 1006 passes the ius delationis —the right to accept or renounce the first deceased's inheritance—. The legal question that has divided scholars for more than a decade is simple to state: when the transferees accept, do they acquire the assets directly from the first deceased, or do they receive them through the transferor's estate?

What changes: two transmissions instead of one

The First Chamber of the Supreme Court has chosen the second answer. STS 849/2026, of 3 June (ECLI:ES:TS:2026:2455), sitting as the Full First Chamber, cassation appeal 3733/2021 and Justice Parra Lucán as reporting judge, corrects the interpretation of article 1006 and returns to the classical or double transmission theory.

That doctrine had been abandoned by STS 539/2013, of 11 September (ROJ STS 5269/2013), First Chamber, reporting judge Orduña Moreno, which established the so-called modern or direct acquisition theory: under it, there was a single transmission, since the transferee acquired the first deceased's assets in their own right, without passing through the transferor's estate.

The new judgment reasons that in succession iure transmissionis there are two successive movements of assets, not one. First, the ius delationis is integrated into the transferor's estate; then, the transferees receive it through that estate. In the court's own words, the value of what corresponded to the transferor in the first deceased's inheritance must be computed in the transferor's estate. The consequence is that, civilly, there are two chained transmissions and not a direct acquisition.

The mandatory participation of the transferor's forced heirs

The most immediate effect of the judgment concerns the partition. If the assets pass through the transferor's estate, those who hold rights over that estate must be taken into account when distributing the first deceased's inheritance.

The Supreme Court states it clearly: in the partition of the first deceased's inheritance, the participation of the transferor's forced heirs is required. Forced heirs are those to whom the law reserves an indisposable portion of the estate, the legítima (reserved share), under articles 806 et seq. of the Civil Code. Among them, the judgment expressly highlights the transferor's surviving spouse, holder of the statutory usufructuary share regulated in articles 834 et seq. of the Civil Code.

From this follows a practical rule worth remembering: in a chained inheritance it is no longer enough for the transferees to accept and divide. The transferor's forced heirs must also take part, notably their widow or widower, whose share is calculated by computing the value that corresponded to the transferor in the first deceased's inheritance. Leaving them out exposes the partition to a later challenge for pretermission or for infringement of the reserved share.

The tax impact: two Inheritance Tax assessments

Which theory applies is not neutral in tax terms. Under the double transmission theory there are two taxable events for Inheritance and Gift Tax, governed by Law 29/1987: one for the succession from the first deceased to the transferor, and another for the succession from the transferor to the transferees. Under the direct acquisition theory, by contrast, a single assessment is argued, because the transferee succeeds the first deceased directly.

Here a tension arises that should be explained precisely. The Supreme Court's own tax doctrine had aligned itself with the modern theory: STS 936/2018, of 5 June, Third Chamber (Administrative), appeal 1358/2017, concluded that in the right of transmission there is a single acquisition for tax purposes, so that the transferee is taxed only once on the succession from the first deceased. The First Chamber's return to double transmission therefore reopens a debate that the Third Chamber appeared to have closed: the civil treatment again points to two successive transmissions, while the prevailing tax doctrine maintains a single one.

Inheritance tax where the heir dies without accepting is, consequently, a matter that requires monitoring. The divergence between the civil and the tax interpretations may translate into a heavier burden, two assessments instead of a single aggregated one, and makes it essential to plan each chained inheritance weighing both doctrines before accepting or dividing.

Frequently asked questions about the right of transmission

When does the right of transmission apply?

It applies when a person is called to an inheritance and dies without having accepted or renounced it. In that case, article 1006 of the Civil Code passes to their heirs the right to accept or reject that first inheritance.

What is the difference between the double transmission theory and the direct acquisition theory?

The double transmission theory holds that the assets pass first to the transferor's estate and from there to the transferees, in two successive transmissions. The direct acquisition theory argued for a single transmission from the first deceased to the transferee. STS 849/2026, of 3 June, has returned to the former.

Must the surviving spouse of the deceased heir take part in the partition?

Yes. Under the new doctrine, the transferor's forced heirs, and in particular their surviving spouse as holder of the statutory usufructuary share, must take part in the partition of the first deceased's inheritance, whose value is computed to calculate their reserved share.

How many times is Inheritance Tax paid in a chained inheritance?

Civilly, double transmission implies two taxable events. However, the Third Chamber of the Supreme Court had allowed a single assessment in STS 936/2018. The coexistence of both doctrines makes it advisable to analyse each case before assessing the tax.

Does this change affect the inheritances of non-residents in Spain?

Article 1006 applies where the succession is governed by Spanish law. In cross-border successions, the applicable law is determined under the European Succession Regulation, a matter we address in our guide on inheritances in Spain for non-residents.

How we help you with inheritances and successions in Murcia at RCM Legal

There are few succession situations as prone to error as chained inheritances. The most common difficulty lies not in accepting, but in identifying everyone who is called: following STS 849/2026, leaving out the transferor's forced heirs, starting with their surviving spouse, turns an apparently closed partition into a challengeable distribution, and overlooking the divergence between the civil and the tax doctrines may double the Inheritance Tax burden. Failing to act well at the outset tends to surface late, once the error has already led to litigation or a supplementary assessment.

At RCM Legal we advise heirs and families on the handling of inheritances and successions in Murcia: we analyse the succession chain, determine who must take part in the partition under article 1006 of the Civil Code, calculate the reserved shares involved, and plan the inheritance tax assessment where the heir has died without accepting. If you would like to place your case within the general framework of Spanish succession, you may consult our guide to inheritances in Spain; and if your situation fits this scenario, tell us about your case and we will study the best way to protect your position.