After buying your Spanish dream home, do you unexpectedly receive a letter titled 'Propuesta de Valoración y de Liquidación Provisional'? Then you have to deal with la complementaria. This is a formal requirement by the Spanish tax authorities to pay additional transfer tax because the declared purchase value is lower than the tax reference value.
In this article, we explain how this procedure works, the impact of the new Valor de Referencia (since 2022) and how you legally seal this.
What exactly is la complementaria?
La complementaria is a supplementary tax assessment issued by the Spanish tax authorities (Hacienda) imposed if they ruled that you were underpaid transfer tax (ITP) paid at the time of purchase.
The law states that the tax authorities may check the tax value of a property. If the actual purchase price in the notarial deed is lower than the value set by the government (the Valor de Referencia or tax value)? Then the tax is calculated on that higher government value. The difference in tax, often plus interest, is recovered through this assessment. This is similar to a deficit assessment in Belgium, but based on automated data.
Expert Quote: "Many buyers think the deal price is automatically the taxable base. In Spain, the taxable base is the higher of the two: the market price or the reference value. Those who ignore this are guaranteed to get mail from the taxman." - Confianz Team.
Why are you receiving this additional tax assessment?
The reason lies in the difference between commercial reality and administrative valuation. Since the property crisis, 'bargains' can still be found in regions like Costa Blanca and Costa del Sol. For example, you buy a resale home at a competitive price.
As a result, the Spanish government is losing revenue from the ITP (Impuesto de Transmisiones Patrimoniales). To compensate for this, since 1 January 2022 the tax authorities have been applying a stricter system: the Valor de Referencia.
The impact of the 'Valor de Referencia' (New Legislation)
Since 2022, the tax value is no longer subjectively estimated, but determined by the Spanish Land Registry (Catastro) based on actual sales figures in the area.
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The rule is simple: You pay tax on the Valor de Referencia, unless the purchase price is higher.
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The risk: Buying a property under this reference value? Then you will pay tax on a value you did not pay. If you do not do this spontaneously, it follows la complementaria.
Calculation example: The financial impact of an audit
To make the impact concrete, we outline a common scenario on the Costa Blanca.
Case study: Apartment in Calpe
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Actual purchase price: €120,000 (A good deal).
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Fiscal Reference Value: €220,000 (Determined by the Land Registry).
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Difference: € 100.000.
The taxman's calculation: The registration tax (ITP) in the Valencia region is 10%.
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You paid 10% at €120,000 = € 12.000.
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Tax authorities claim 10% at €220,000 = € 22.000.
The result: You will receive a complementaria from € 10.000 (the difference), plus default interest.
What taxes and fees do I pay when buying a property in Spain?
How can I avoid an additional assessment?
Avoiding an additional attack begins before signing the notarial deed. Subsequent objections have become more complex since the 2022 law change, as the burden of proof is now on the buyer to prove that the cadastral value is incorrect.
Preventive steps we take during purchase counselling:
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Check the Valor de Referencia: We request the official value certificate from the Land Registry before purchase.
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Anticipate the load: Is the reference value higher than your purchase price? If so, we recommend paying transfer tax on the reference value immediately. This will avoid penalties and interest afterwards.
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Technical counter-expertise: Is the reference value unrealistically high (e.g. due to the poor condition of the property)? Then we build a file with an independent valuation report to officially dispute the value before the tax becomes final.
Find more information on the new valuation method here.
Frequently asked questions (FAQ)
Is the Valor de Referencia the same as the Cadastral Value? No. The cadastral value (Valor Catastral) is often a low value that serves for annual council tax (IBI). The Valor de Referencia is a market-based value that specifically serves as a minimum basis for purchase taxes.
Can I object to la complementaria? Yes, but the burden of proof is on you. You have to prove that the property is worth less than the Land Registry claims, for example due to structural defects. This requires a legally supported valuation report.
Does this rule also apply to new construction? No. With new construction, you do not pay transfer tax (ITP), but VAT (IVA) and Stamp Duty (AJD). The Valor de Referencia is mainly relevant for existing construction (resale).
How do I know the tax value of my future home? This value is publicly retrievable through the Spanish Land Registry's digital window (Sede Electrónica del Catastro) using the property's cadastral reference.
About the author: Glenn Janssens is a lawyer specialising in Spanish real estate transactions and tax regulations. Since 2017, he has been helping Belgian and Dutch individuals and entrepreneurs to safely purchase and structure real estate in Spain. He guides files from A to Z: from due diligence, ownership and tax control to estate planning and optimisation for residents and non-residents. Thanks to his years of experience, hundreds of handled files and focus on transparent communication, Glenn makes complex Spanish legislation understandable and practically applicable for every property buyer.
Last update: December 2025
