The Spanish Supreme Court reiterates the doctrine on the foreign tax residence certificate, but the first tie-breaker rule of the treaty places residence in Spain, the only State where a permanent home is recorded

The Third Chamber of the Spanish Supreme Court, in judgment 971/2025 of 15 July (cassation appeal 4023/2023, Judge Rapporteur Navarro Sanchís), reiterates the doctrine of STS 778/2023 of 12 June on the presumption of validity of a foreign tax residence certificate issued for the purposes of a double taxation convention.

The Court criticises the tax authorities for having “abruptly dismissed the tax residence certificate, without giving the slightest indication of where its lack of probative value might lie”, a course of action that, it says, “openly contravenes our consistent case law” (our translation). Even so, it dismisses the appeal. The taxpayer had a permanent home in Spain and identified none in the United Kingdom, so the first tie-breaker rule in article 4.2 of the Spain–United Kingdom convention places his residence in Spain.

The legal framework

Article 9.1 of Law 35/2006 of 28 November on Personal Income Tax (LIRPF) sets the criteria under which individuals are treated as tax resident in Spain. STS 778/2023 requires a residence conflict to be recognised where the taxpayer also produces a residence certificate from the other State issued for treaty purposes.

Article 4 of the Spain–United Kingdom convention, signed in London on 14 March 2013, follows the OECD Model. Paragraph 1 defines a resident by reference to each State’s legislation; paragraph 2 resolves dual residence through successive rules, the first being a permanent home available. Order EHA/3316/2010, which the Supreme Court relies on, requires the certificate to state that the taxpayer is resident “within the meaning of the Convention” (our translation).

The case

Mr Fausto, a British pensioner with a home in San Roque (Cádiz) and registered on the municipal roll of Estepona (Málaga), received provisional personal income tax assessments for 2014, 2015 and 2016 of EUR 13,622.86, 13,075.86 and 13,406.32, and the related penalties, which the lower court annulled.

The tax authorities based the assessments on several facts: a home in San Roque since 23 May 2008, with no other recorded in the United Kingdom; registration on the Estepona municipal roll since at least 2014; registration since 2013 on the list of foreigners resident for healthcare purposes, through form S1; vehicles registered in Spain with an Estepona address; and information sent by the UK tax authority, according to which the taxpayer had told his UK payer that he was tax resident in Spain.

The taxpayer produced a UK tax residence certificate issued for treaty purposes, his UK tax returns, withholding certificates for his UK pension from 2014 to 2019 and his passport. The High Court of Justice of Andalusia (Málaga), in judgment 453/2023 of 15 February (appeal 723/2021), annulled the penalties but upheld the assessments: only one permanent home was on record, the one in Spain.

The question referred and the doctrine reiterated

The order admitting the appeal, of 6 March 2024, raised three questions literally identical to the first three in appeal 915/2022, decided by STS 778/2023. The Court, “given the substantial identity between that case and the one we must now decide” (our translation), refers to that doctrine and reiterates its three points: national bodies may not assess the circumstances in which the certificate was issued or disregard its content; its validity must be presumed; and a State may not unilaterally decide a residence conflict without applying the convention’s rules, interpreted autonomously. Legal Ground Seven is headed “Case law established”, although the ruling refers to the criteria “set out in Legal Ground Six”.

Criticism of the tax authorities and the lower court

The judgment is particularly critical of how the certificate was treated. In this case, it notes, there was no general disparagement of a country’s certificates, but there was “a total and absolute failure to assess it formally and substantively” (our translation), at the administrative and judicial stages, as if the certificate did not exist.

The Court puts it this way: “if the residence certificate, embodied in an official document, attests to a fact relevant to establishing tax residence in a given State —not in another—, as we have repeatedly stressed, it is not admissible, lawful or appropriate from the standpoint of international law as crystallised in double taxation conventions for any official, unilaterally, to be free to take the certificate into account or not” (our translation). At the same time, it acknowledges that the matter lacks precise regulation: “there is no rule whatsoever, of a treaty nature” clarifying which authority may certify or what the certificate must state.

The judgment describes the presumption arising from the certificate as “at least iuris tantum” —that is, at the very least a rebuttable presumption— and criticises the lower court for having improperly downplayed it.

Why the appeal is dismissed

There are two reasons. First, the appellant himself, in his notice of appeal, relied on the tie-breaker rules of article 4.2 of the convention. For the Court, “the appellant’s very submission to the rules set out in the convention amounts to an acknowledgement that, despite the residence certificate issued and produced, he denies or at least relativises its probative value for establishing tax residence” (our translation).

Second, once those rules are applied, the first of them “is decisive in resolving the dispute”. It is not plausible, the Court says, that the taxpayer had a home in the United Kingdom, “since, had that been the case, it would have been extremely easy for him simply to state his address in that country during the period 2014-2016 or some other detail identifying the home he kept available in the United Kingdom” (our translation). His claim that his presence in Spain was limited to holidays was made “without the slightest evidential support” and sat ill with the permanent home in Spain, the municipal registration and the healthcare card.

The lower court, although it ignored the certificate, assessed the evidence and applied the permanent home rule, so its conclusion was neither illogical nor irrational. The ruling dismisses the appeal. The Court expressly leaves unexamined other facts that, properly presented, might have been relevant, such as taxation in the United Kingdom or the withholding regime for the pensions.

Our assessment

In our view, the judgment can be read in two ways. The first confirms the doctrine: the tax authorities may not ignore a certificate issued for treaty purposes, and the Court says so clearly. The second marks its limit: the certificate opens the conflict but does not resolve it. Once the tie-breaker rules apply, evidence of ties with each State is decisive, starting with the home.

The appellant’s strategy, which relied both on the certificate and on the tie-breaker rules, worked against him, although the outcome would probably have been the same: with the certificate, the conflict still had to be resolved under article 4.2, and a permanent home was only on record in Spain.

The fact that weighed most heavily against him, in our view, was the inconsistency of his own conduct. He had told his UK payer that he was resident in Spain, and that information reached the Spanish tax authorities through the exchange of information.

Practical consequences

Anyone claiming residence in the United Kingdom should be able to identify their home there precisely —address, title deed or lease, utilities— throughout the period. A general claim of residence, even backed by the certificate, is not enough.

STS 971/2025 does not address when the certificate should be obtained. As a precaution, it is advisable to obtain it every year and keep it, although STS 778/2023 accepted certificates produced only at the administrative appeal stage.

It should also be borne in mind that the continuous availability of a home in Spain may be enough for it to count as permanent, even if it is used only for holidays. And all the taxpayer’s statements —to the payer, to financial institutions and to the tax authorities of both States— must be consistent with the residence claimed.