Tax Disputes: Expert Defence Against AEAT Inspections

Tax litigation in Spain encompasses the administrative and judicial procedures available to taxpayers to contest assessments, penalties, and decisions issued by the Spanish Tax Agency (AEAT), governed by the General Tax Act (Law 58/2003, LGT) and the General Regulation on tax management and inspection proceedings (Royal Decree 1065/2007). The compulsory prior step before going to court is the economic-administrative claim — filed before the Regional Economic-Administrative Court (TEAR) for assessments up to EUR 150,000 or the Central Economic-Administrative Court (TEAC) for higher amounts — after which taxpayers may appeal before the Tribunal Superior de Justicia, the Audiencia Nacional, or ultimately the Tribunal Supremo; tax penalties for infringements range from 50% to 150% of the unpaid quota, though the LGT provides reductions of 30% for conformity with the liquidation proposal and an additional 25% for timely payment.

Tax law is one of the areas where specialist technical assistance makes the greatest difference between a taxpayer who knows their rights and one who does not. The tax administration has considerable technical and human resources; a taxpayer facing an inspection without specialist advisers typically starts from a position of informational disadvantage that translates into worse economic outcomes than professional defence would achieve.

Why Defending Against the AEAT from Day One Makes the Difference in Tax Disputes

An AEAT inspection is a situation of radical informational asymmetry. The Administration knows its own criteria in depth, has access to cross-referenced data from all the taxpayer’s declarations, and has between 18 and 27 months to examine the four non-statute-barred years. The taxpayer without specialist representation from day one tends to over-cooperate, providing information that was not requested and weakening their defensive position. The typical result is a provisional assessment that the taxpayer accepts without evaluating whether it could successfully be appealed — forgoing appeal routes that, in expert hands, resolve favourably in more than 70% of cases before the TEAR or TEAC.

Our Tax Dispute Defence Process: From Inspection Through to the Tribunal Supremo

Our tax dispute specialists engage from the initial notification. In the inspection phase, we represent the taxpayer before the inspectors: we manage every communication, determine what information must be provided and how to present it most favourably, and submit technical allegations against the proposed assessment. If the inspection deed is unfavourable, we assess the probability of success through each route — conformity with a 30% penalty reduction versus disagreement with appeal — and recommend the strategy that maximises the economic outcome. In the economic-administrative route, we prepare claims before the TEAR and TEAC with grounds rooted in administrative doctrine and current Tribunal Supremo case law. Where the matter justifies it, we take the case to the contentious-administrative route before the TSJ or the Audiencia Nacional.

Regulatory Framework: LGT, Inspection Procedure, and Appeal Routes

The inspection procedure is governed by Law 58/2003 (General Tax Act) and the General Regulation on tax management and inspection proceedings (Royal Decree 1065/2007). The general inspection timeframe is 18 months, extendable to 27 months for special complexity cases or consolidated groups. Tax penalties range from 50% to 150% of the unpaid quota depending on the infringement category (minor, serious, or very serious) and the presence of concealment. The economic-administrative route — a claim before the TEAR for assessments below EUR 150,000 and before the TEAC for higher amounts or doctrine matters — is mandatory before going to court. Criminal tax law under the Penal Code applies when the defrauded quota exceeds EUR 120,000.

Real Results in Tax Disputes: 78% Success Rate and Average 60-70% Reduction

• Average reduction of 60-70% of the initial proposed assessment in inspections managed from the outset.
• 78% success rate in economic-administrative claims submitted before the TEAR and TEAC.
• Elimination or substantial reduction of tax penalties through the correct conformity or challenge strategy.
• Voluntary regularisation of historical contingencies with surcharges of 5-20% instead of penalties of 50-150%, where acting before the AEAT initiates proceedings is appropriate.
• Preventive documentation of the defensive position: documentation of high-exposure transactions before any review.

The AEAT inspection procedure is a regulated process with very specific deadlines, rights, and obligations. The right not to self-incriminate, the right to review the file, the right to request justified delays, and the right to submit allegations before signing the deed are taxpayer guarantees that must be actively exercised. Many taxpayers, through lack of knowledge or in the belief that unconditional cooperation is the best strategy, effectively waive guarantees that could change the outcome of the procedure.

The economic-administrative route resolves in the taxpayer’s favour in a significant percentage of cases, particularly on penalties and the application of tax benefits denied by the inspector through restrictive interpretation. The TEAC’s published doctrine and Tribunal Supremo case law are technical instruments whose command requires specialisation, but which in experienced hands allow the construction of high-quality arguments. Our tax compliance team works in close coordination with the litigation team to ensure positions adopted in returns are consistent and defensible against any future inspection.

The preventive dimension of tax litigation is as important as the defensive one. Identifying and quantifying historical tax contingencies, assessing the risk of voluntary regularisation against the risk of inspection, and robustly documenting high-exposure transactions are investments that significantly reduce the probability and cost of future disputes. When a company undergoes an M&A transaction, the seller’s potential tax litigation is one of the liabilities the buyer must identify and quantify in due diligence, with appropriate contractual guarantees structured accordingly.

The Spanish tax dispute resolution framework

Tax litigation in Spain follows a structured administrative and judicial pathway that begins with the AEAT inspection process and ends, if necessary, in the courts. Understanding each stage — and the strategic choices available at each point — is essential for obtaining the best possible outcome.

The formal framework comprises:

1. AEAT inspection (actuación inspectora): the AEAT conducts its investigation, culminating in an acta (settlement proposal) — either de conformidad (agreed, with reduced penalties) or de disconformidad (contested).
2. Administrative review (recurso de reposición): a first-instance review by the same AEAT body that issued the assessment. Mandatory before proceeding to the TEAC, but typically has low success rates as the reviewing body rarely overturns its own decisions.
3. TEAC — Tribunal Económico-Administrativo Central: Spain’s specialised tax review tribunal, independent from the AEAT. The TEAC can annul or modify AEAT assessments on both procedural and substantive grounds. Success rates at TEAC are significantly higher than at reposición level.
4. Contencioso-administrativo — Audiencia Nacional or Tribunales Superiores de Justicia: judicial review of TEAC decisions before the courts. The Audiencia Nacional has jurisdiction for cases decided by the TEAC; the TSJ has jurisdiction for decisions of regional TEARs.
5. Tribunal Supremo: cassation review of Audiencia Nacional or TSJ decisions where there is legal interest in doctrine.

AEAT inspection defence: the critical phase

The outcome of a tax dispute is frequently determined during the inspection phase — before any formal dispute resolution process begins. The quality of the response to the AEAT’s initial information requests (diligencias, requerimientos), the documentation provided, and the technical arguments advanced at the inspection stage significantly influence the final acta.

Key principles in AEAT inspection defence:

• Respond fully and accurately: incomplete or evasive responses to AEAT requests increase the AEAT’s suspicion and may be used to support adverse factual conclusions.
• Preserve procedural rights: the AEAT is required to follow specific procedural rules (plazos, notificaciones, actuaciones) and failures to do so can be grounds for annulment at TEAC or judicial level. Our team identifies and preserves procedural arguments throughout the inspection.
• Challenge expert determinations: where the AEAT relies on expert valuations or technical assessments, we provide counter-expertise through independent experts with professional standing before the AEAT and the courts.
• Negotiate actas de conformidad carefully: agreeing an acta de conformidad (which reduces penalties by 30% and provides certainty) may be the right outcome in some cases but must be evaluated against the merits of contestation.

Transfer pricing disputes

Transfer pricing disputes are the single most common form of AEAT inspection for large companies, and also the most complex. The AEAT’s transfer pricing inspection team applies econometric and functional analysis to challenge arm’s length positions, and the documentation requirements are exacting. Our transfer pricing team works alongside our litigation team in these cases, providing the technical substance while litigation specialists manage the procedural strategy.

Advance Tax Rulings (Consultas Vinculantes)

Rather than litigating a tax uncertainty, companies can seek a binding advance ruling (consulta tributaria vinculante) from the DGT (Dirección General de Tributos). A favourable ruling binds the AEAT for transactions described in the consultation, providing certainty at a fraction of the cost of litigation. Our advisory team prepares and manages the consulta process for clients seeking certainty on novel or complex tax positions.

Contact our tax litigation team for a confidential assessment of your AEAT inspection or dispute resolution strategy.