Ius transmissionis: what it is, how it works and what has changed

At that moment, the ius transmissionis or right of transmission comes into play, one of the most debated institutions in Succession Law. Although its regulation in the Civil Code occupies barely a line, it has given rise over more than a century to intense doctrinal debates, numerous resolutions from the Directorate General of Registries and Notaries — today Directorate General of Legal Security and Public Faith — and some of the most important rulings of the Supreme Court in succession matters.

It might seem a discussion reserved for jurists. Nothing could be further from the truth. The answer determines who must appear in a deed of acceptance of inheritance, who has the right to intervene in the hereditary partition, what is the position of the surviving spouse or the forced heirs, and even what the consequences may be in the Inheritance Tax.

In a notary’s office, this scenario appears much more frequently than is usually imagined. It is enough that a few months pass between the deaths of two relatives for an apparently simple succession to become a much more complex procedure. It is precisely in these cases when notarial advice acquires its full meaning: to correctly reconstruct the succession chain and offer the family the legal certainty necessary to accept the inheritance with all guarantees.

For years it seemed that the issue had been definitively resolved after the historic Supreme Court Ruling of 11 September 2013, which represented a true paradigm shift. However, the recent Ruling of the Plenary of the First Chamber of the Supreme Court of 3 June 2026 has once again placed the ius transmissionis at the centre of the succession debate.

In this article, we will explain what the right of transmission is, how its interpretation has evolved, what changes after the new case law, and what practical consequences it has for those who must process an inheritance.

The best way to understand this institution is to look at an example.

The legal basis of the right of transmission is found in article 1006 of the Civil Code, which states that “by the death of the heir without accepting or renouncing the inheritance, the same right that he had shall pass to his own.”

It is surprising to see that an institution that has generated so much doctrine and jurisprudence is supported by such a brief provision.

And precisely there the problem begins.

The legislator explained what is transmitted, but did not clarify how that transmission should be understood nor what its effects were.

The doubt was not minor.

Who really acquired the status of heir of the first deceased?

Is the first deceased inherited or the transmitter?

What role did the surviving spouse or the forced heirs of the transmitter play?

Was it necessary to first accept the inheritance of the transmitter in order to decide on that of the first deceased?

For decades there was no unanimous answer. Doctrine developed different legal constructions and notarial and registry practice coexisted with solutions that did not always coincide.

Few institutions have evolved as much as ius transmissionis.

For much of the twentieth century, the so-called classical theory prevailed. According to this interpretation, when the transferor died without accepting the inheritance, it first became integrated into their hereditary estate and was subsequently acquired by their own heirs. Therefore, there were two successive transfers.

It was a legally coherent construction and was accepted for years by much of the doctrine, by notarial and registry practice, and by the resolutions of the former Directorate General of Registries and Notaries.

However, doubts gradually began to arise.

The main one was as simple as it was difficult to answer.

The acceptance of inheritance has always been a voluntary act. If the called party died without accepting or repudiating it, it was debatable to maintain that such inheritance had actually become incorporated into their estate.

From this reflection, a new doctrinal current began to consolidate: the so-called theory of direct acquisition.

According to this interpretation, the transferees did not inherit from the transferor the assets of the first deceased, but only the right that the latter had to accept or repudiate the inheritance. Once this right was exercised, they directly acquired the status of heirs of the first deceased.

For years, both theories coexisted in doctrine and practice, generating notable legal uncertainty. The situation eventually reached the Supreme Court, which had to rule on a controversy that had been open for more than a century.

The answer came with the Supreme Court Judgment of 11 September 2013, probably one of the most influential rulings in Spanish succession law in recent decades.

The High Court expressly embraced the theory of direct acquisition and abandoned the classical construction that had predominated until then. The ruling was received as a genuine turning point and marked notarial and registry practice in the following years.

The new doctrine was quickly adopted by the General Directorate of Registries and Notaries, whose Resolutions of 26 March 2014 and 11 June 2014, among many others thereafter, began to adapt registry practice to the new jurisprudential criterion and to resolve the first issues arising around the intervention of heirs, forced heirs and other interested parties in the division of the inheritance.

It seemed that, finally, the debate had been definitively resolved.

But succession law has a curious habit: when a great judgment seems to close a discussion, it almost always opens new ones.

All these issues gradually reached the Directorate General and the courts. The notarial practice played an essential role here, because it was in the notaries' offices where these problems ceased to be theoretical and became real cases.

Those of us who regularly work in succession law know that behind the ius transmissionis there is rarely a single inheritance. It is common to encounter several linked successions, different wills, heirs belonging to different family branches, and even different succession laws. Therefore, before drafting a deed of acceptance of inheritance, it is essential to reconstruct the entire succession chain and correctly determine who are the persons called to intervene.

When it seemed that the legal landscape had stabilised, the Full Court of the First Chamber of the Supreme Court once again ruled on the right of transmission through its Judgment of 3 June 2026.

The importance of this ruling goes far beyond the specific case it resolves.

The Supreme Court reflects again on the nature of the ius transmissionis and reconsiders the interpretation that had governed this matter since 2013. Essentially, it understands that the right of transmission cannot be analysed in isolation, but within the whole phenomenon of succession and the general rules that govern the acquisition of inheritance.

One of the most relevant aspects of the judgment is to recall that the ius delationis forms part of the estate of the transferor. Consequently, in order to exercise that right, it is essential to have previously acquired the status of heir of the transferor by accepting their inheritance.

This approach represents an important evolution compared to previous doctrine and requires reconsidering practical issues that many legal practitioners already considered settled.

It will be necessary to see how the doctrine of the Directorate General for Legal Security and Public Faith, subsequent case law, and registration practice evolve. However, it is undeniable that this judgment will shape the interpretation of article 1006 of the Civil Code over the coming years.

The right of transmission in Catalonia is also expressly regulated, although within the succession system of the Civil Code of Catalonia.

Article 461-13.1 establishes that, if the person called to an inheritance dies without having accepted or renounced it, the right to do so is transmitted to their heirs.

For those of us who perform notarial functions in Catalonia, this issue has extraordinary practical importance. A large number of the inheritances authorised daily are governed by Catalan civil law and not by the common Civil Code. This requires determining, before initiating any succession procedure, which law is applicable to the succession.

Although the practical purpose of article 461-13.1 of the Civil Code of Catalonia bears obvious similarities to article 1006 of the Civil Code, it is not advisable to automatically transfer the doctrine developed for common law. The Catalan legal system has its own principles in succession matters and the interpretation of its institutions must be carried out taking into account the systematics and purpose of the Civil Code of Catalonia itself.