The Constitutional Court has admitted the challenge of unconstitutionality raised by the High Court of Justice (TSJ) of Andalusia against the Cadastre reference value. This value, in force since 2022, is used as the tax base for key taxes such as the Property Transfer Tax (ITP) and the Inheritance and Gift Tax (ISyD). The decision to admit the appeal opens a legal and tax debate that could have a huge impact on thousands of taxpayers.
Why is the unconstitutionality being raised?
The ruling of the High Court of Justice of Andalusia, dated May 5, 2025 (appeal 385/2024), questions the methodology used to set the reference value. According to the court, it is a massive method, based on parameters that are opaque to the public, and relies on unrepresentative samples of transactions. This system does not consider fundamental characteristics of the properties, such as useful area, state of repair, quality of materials, or the existence of annexes (storage rooms, garages, gardens).
The Andalusian court warns that this method can lead to results that are far removed from market reality, with identical values for properties with very different conditions. This raises concerns about the possible existence of a fictitious encumbrance that could violate the principle of economic capacity enshrined in Article 31.1 of the Spanish Constitution.
For this reason, the High Court of Justice of Andalusia has raised the unconstitutionality of Articles 10.2, 10.3, and 10.4, and Article 46.1 of the Property Transfer Tax Law (Royal Legislative Decree 1/1993), as well as the third final provision of the Consolidated Text of the Real Estate Cadastre Law.
What are the consequences of admissibility for processing?
The admission of the constitutionality question serves as a warning to thousands of transactions already carried out and future ones. Until the Constitutional Court issues a ruling, the assessments and self-assessments of the Property Transfer Tax (ITP) and the Income Tax (ISyD) in which the reference value was applied remain in question.
Attorney José María Salcedo, a tax litigation specialist, points out that the Constitutional Court frequently limits the effects of its unconstitutionality rulings to only those taxpayers who had initiated a claim before the ruling was issued.
Therefore, he recommends appealing the assessments and requesting rectification of the self-assessments in which the reference value was applied, and keeping the appeals open until the final ruling is issued.
Furthermore, although the constitutionality question focuses on the Property Transfer Tax (ITP), it also indirectly affects the Income Tax (ISyD), since both taxes share the same reference value for calculating the tax base. In this regard, it is also advisable to challenge ISyD settlements even if it is not explicitly mentioned in the TSJ ruling.
How the reference value is calculated and why it is in question
The reference value is an annual estimate made by the General Directorate of Cadastre based on sales actually completed and formalized before a notary. However, its calculation is complex and opaque.
The process is based on a statistical analysis of average prices in each geographical area, but does not include an individual analysis of each property. Thus, essential aspects such as state of repair, renovations, orientation, views, interior layout, etc. are ignored.
The Spanish Association of Tax Advisors (AEDAF) has criticized this methodology, considering it contrary to the constitutional principles of economic capacity and tax legality. The AEDAF has challenged the annual resolutions that set the reference value and has asked the National Court to raise a similar constitutional challenge.
The comparison with the case of municipal capital gains tax is inevitable. In 2021, the Constitutional Court declared the method for calculating municipal capital gains tax unconstitutional for taxing fictitious, rather than real, income. The reference value could suffer the same fate if it is confirmed that it is taxed on a fictitious, non-market value.
How to find out the reference value of your property?
The reference value is especially important in the purchase and sale of used homes or in inheritances and donations. Tax is always based on the higher of the values: the registered value or the reference value.
For example, if you buy a property for €200,000 but the reference value is €250,000, you will have to pay taxes on the latter amount, which can add up to several thousand euros.
You can check the reference value of a property in three ways:
Online: Accessing the Cadastre Electronic Office with a digital certificate, DNIe (e-ID card), or Cl@ve (Clave).
Telephone: Call 91 387 45 50 or 902 37 36 35.
In person: Request an appointment at the Cadastre Office.
Conclusion: What should taxpayers do?
The open constitutionality issue is an opportunity for taxpayers to review their recent transactions and consider filing claims.
Those who have already filed appeals should keep them active and add the allegation of unconstitutionality to safeguard their rights. Those who have not yet done so should consider filing an appeal so as not to lose the option of recovering overpaid amounts if the Constitutional Court ultimately declares the reference value unconstitutional.
We will be attentive to the publication of the issue in the Official State Gazette (BOE) and the future ruling, which could redefine the real estate tax system in Spain and put an end to the controversy surrounding the reference value as we know it today.
At Cardador&Marín Abogados, we can advise and assist you in this process with complete guarantees and security.