Reflections from our contribution to the Chambers Tax Controversy Global Practice Guide 2026
We are pleased to have been invited by Chambers and Partners to contribute the Trends and Developments chapter on Spain to the latest edition of the Chambers Tax Controversy Global Practice Guide 2026. The chapter examines the most consequential developments shaping Spanish tax controversy practice for international high net worth individuals over the past eighteen months, and the strategic implications for those who reside in Spain, hold assets here, or are considering relocating to the jurisdiction.
The full chapter is available on the Chambers and Partners website. The following note offers a condensed overview of the principal themes and the practical conclusions we draw from them.
A clear strategic reorientation
For much of the last decade, Spanish tax controversy involving high net worth individuals tended to follow a predictable arc. Inspections were principally documentary, focused on the formal accuracy of returns, the timely filing of foreign asset declarations and the proper application of bilateral tax treaties. The substantive correctness of the underlying structures was rarely the principal battleground.
That period is over. Over the course of 2025 and into 2026, the Spanish Tax Agency (AEAT) has executed a clear strategic shift. Inspections of internationally mobile clients are now substance-driven, evidence-intensive and frequently framed within the conceptual category of simulation under Article 16 of the General Tax Act. The most visible manifestation has been the surge in audits of beneficiaries of the special inbound expatriate regime under Article 93 of the Personal Income Tax Act, popularly known as the Beckham Law, but the underlying methodology now extends across the full spectrum of cross-border private client tax matters.
The 2026 Tax Control Plan reflects this reorientation explicitly. The expansion of the Financial Ownership File, the gradual implementation of the Verifactu system, and the transposition of DAC 8 with effect from 1 January 2026 together provide the AEAT with an unprecedented data architecture for cross-checking declared positions against the operational reality of the taxpayer. Inspectors now interrogate bank flows, professional digital footprints, corporate communications, governance documentation and the geographical origin of decision-making. The question is no longer whether the relevant returns have been filed, but whether the structure they present reflects what actually happened.
Beckham Law audits as the leading indicator
The audits of Beckham Law beneficiaries that have come before us in 2026 do not, in the main, challenge the mathematical accuracy of the Modelo 151 return. They challenge the legal premise of the inclusion in the regime itself. Inspectors scrutinise whether the cause of the residency in Spain is genuinely the new employment relationship presented to the AEAT, or whether that employment is, in substance, a vehicle constructed to ring-fence pre-existing foreign income from Spanish taxation. Where the AEAT concludes the latter, it has shown an increasing willingness to revoke the regime retroactively, with consequences extending across all open years.
Three recurring fact patterns are driving these outcomes. The first involves newly incorporated Spanish companies with limited substance, which formally employ the impatriate while the operational invoicing continues to flow through related foreign entities. The second concerns founders and consulting professionals who execute work from a fixed location in Spain, often a home office, giving rise to a de facto permanent establishment of their foreign company. The third arises where the impatriate has retained directorships, signing authority or operational decision-making over foreign companies, and the AEAT contends that the place of effective management has shifted to Spain.
In each scenario, the AEAT increasingly does not confine itself to a technical breach of Article 93. It seeks the more powerful remedy of recharacterisation through simulation, which permits retroactive revocation of the regime and unlocks a meaningfully more severe sanctioning framework.
The procedural architecture: Articles 13, 15 and 16
Understanding which procedural tool the AEAT is deploying is now essential to any defence strategy. The General Tax Act provides three distinct anti-avoidance instruments, each with different evidentiary thresholds, procedural requirements and consequences.
Article 13 permits the recharacterisation of a transaction in accordance with its true legal nature, regardless of the label chosen by the parties. It does not, on its own, support the imposition of penalties where the underlying facts have been disclosed.
Article 15 addresses what Spanish doctrine calls the conflict in the application of the tax norm, and is the closest equivalent in Spanish law to a general anti-abuse rule. Its application requires a prior favourable report from the Consultative Commission, a procedural safeguard the omission of which will render the assessment void. Article 15 also expressly excludes the imposition of penalties.
Article 16, governing simulation, is the most consequential of the three. Where simulation is established, the regime in question is revoked retroactively, the conduct is automatically classified as very severe, and a minimum penalty of 100% of the underpaid tax applies, rising to 125% or 150% where aggravating factors are present.
A central defensive battleground in 2026 is the question of which article the AEAT is actually invoking. We continue to encounter assessments framed as simulation under Article 16 in circumstances where the underlying allegation is genuinely one of artificiality, which is the proper province of Article 15. Where this occurs, the assessment is vulnerable to annulment on procedural grounds, both because the Consultative Commission report has not been obtained and because the sanction shield of Article 15 has been improperly bypassed. The Spanish Supreme Court has been increasingly willing to enforce this distinction, and it remains one of the most fruitful avenues of challenge available to taxpayers.
The permanent establishment question
Among the most significant developments of 2025 and 2026 has been the emergence of the permanent establishment thesis as a recurring feature of Beckham Law and broader expatriate inspections. Article 93 conditions access to the regime on the absence of income obtained through a permanent establishment in Spain, and the AEAT now applies this condition with a confidence and breadth that was not previously evident.
The argument unfolds in a recognisable pattern. The taxpayer is found to operate from a fixed place in Spain, frequently a home office or a co-working space, and the inspectorate concludes that this constitutes a fixed place of business of the foreign company through which the taxpayer carries on its activity. Where supported by evidence of habitual decision-making, contract negotiation or service execution from Spain, the consequences are twofold: the taxpayer loses the regime, and the foreign entity is exposed to a corporate-level permanent establishment assessment, with all the corporate income tax, VAT and registration consequences that implies.
This trend has particular implications for founders, consultants and senior executives whose work is by its nature mobile and difficult to localise. The defensive answer is rarely retrospective. The permanent establishment analysis must be conducted proactively, before entry into the regime, and activity, governance and documentation must be structured to support the position that the foreign company is not operating through a Spanish base.
Modelo 720, Modelo 721 and the continuing evolution of foreign asset reporting
The judgment of the Court of Justice of the European Union in Case C-788/19 dismantled the most punitive features of the Spanish foreign asset reporting regime in 2022, but the obligation to report foreign assets through Modelo 720, and crypto holdings through Modelo 721, remains very much in force. The compliance framework is now better calibrated to EU law, but enforcement activity has not abated; if anything, the AEAT’s data sources have improved markedly through DAC 8 and the expansion of automatic exchange.
The disputes we are now seeing in this area tend to focus on three issues: whether the taxpayer was tax resident in Spain in the year of the alleged reporting failure, which has become a contested question in cases involving cross-border mobility; whether reportable thresholds were properly assessed across asset categories that have grown more complex with the proliferation of digital assets, holding structures and life-insurance-wrapped investment products; and the proportionality of the residual sanctioning regime in light of CJEU principles. In practice, Modelo 720 and Modelo 721 disputes are increasingly tax residency disputes in disguise. The AEAT will frequently use a reporting failure as the procedural entry point for a more substantive challenge to the taxpayer’s residency status.
The Solidarity Tax and the wealth tax front
The Solidarity Tax on Large Fortunes, introduced as a temporary measure in 2022 and subsequently extended, has produced its own distinct controversy stream. The interaction between the state-level Solidarity Tax and the autonomous community wealth taxes has generated technical disputes concerning the deductibility of regional wealth tax liabilities, the treatment of exemptions for business assets, and the valuation of holdings in private companies and family offices.
For high net worth residents of Madrid, Andalusia and other regions where wealth tax has been substantially or wholly relieved, the Solidarity Tax has effectively reinstated a national wealth tax floor that cannot be neutralised through regional planning. These developments are compounded by autonomous community asymmetry: the same family group, holding assets across multiple Spanish regions, may face materially different enforcement postures depending on the location of its assets and members. Cross-border families with Spanish exposure must therefore navigate not only the AEAT but a patchwork of regional authorities whose interpretive positions can diverge significantly.
The documentary standard
A common thread runs through the trends described above. The Spanish tax controversy environment of 2026 is one in which the documentary standard expected of taxpayers has risen sharply. The AEAT builds its case on facts, often assembled through forensic examination of bank flows, digital communications and public information. Defences mounted on explanation and assertion alone, however technically sound, frequently fail to displace that factual narrative.
What is required in practice is contemporaneous evidence addressing three questions across the relevant period. What was the legal and economic substance of the structure, and is it supported by contracts, mandates, board resolutions and operational records that existed at the time? Where did decision-making actually occur, and is that location demonstrable through travel records, meeting minutes, communications metadata and signing protocols? And what was the commercial rationale for the arrangement, defensible independently of any tax consideration?
Documentation produced for the inspection itself, however carefully drafted, carries diminished evidentiary weight. The AEAT and the economic-administrative tribunals are experienced in distinguishing genuine contemporaneous records from reconstructions, and the latter are frequently treated as confirmatory of the AEAT’s substance concerns rather than as a defence against them.
Strategic choices in the inspection phase
The increased importance of strategic decision-making during the inspection phase itself, before any assessment is issued, deserves particular comment. Spanish procedure permits the taxpayer to enter into an acta con acuerdo, securing a meaningful reduction in penalties in exchange for waiver of the right to challenge, or an acta de conformidad, which produces a 30% penalty reduction while preserving the right to challenge the underlying liability.
These options must be weighed against the merits of the case and the appetite for litigation. Where the inspection is unreceptive to substantive arguments, the taxpayer’s interests are often better served by building the evidentiary record for subsequent challenge before the Regional Economic-Administrative Courts and, ultimately, the contentious-administrative jurisdiction. Where, by contrast, the inspector demonstrates a genuine willingness to engage with the technical merits, a negotiated outcome may secure a materially better economic result while preserving relationships with the authority for the future. The decision turns on a careful assessment of facts, evidence, procedural posture and the likely trajectory of the dispute through the appellate system; it is not a decision that should be made under pressure, nor without an integrated view of the taxpayer’s broader international affairs.
Looking ahead
The trajectory is clear. The Spanish tax controversy environment over the next eighteen months will be defined by a continued intensification of substance-based enforcement, deeper data integration through DAC 8 and Verifactu, and sustained scrutiny of internationally mobile taxpayers and the structures through which their affairs are conducted.
For high net worth individuals and their advisers, the implications are practical and immediate. Structures must be designed for substance, not merely for documentary defensibility. Contemporaneous evidence must be assembled and maintained as a matter of operational discipline. The choice of procedural route, when controversy arises, must be made with an integrated view of facts, evidence and the likely trajectory of any subsequent challenge.
The Spanish tax authority is no longer a documentary checker. It is a sophisticated, well-resourced and increasingly assertive regulator, operating with a data infrastructure that exposes inconsistencies between form and substance with a precision that did not previously exist. The clients who navigate this environment successfully will be those whose advisers have understood the shift and prepared accordingly. Those who treat tax controversy as a matter for after the notification arrives will find themselves at a structural disadvantage from which recovery is difficult and expensive.
How we advise
At Lullius, tax controversy is a core practice area. We regularly represent international clients in inspections by the AEAT, in proceedings before the Regional and Central Economic-Administrative Courts (TEAR and TEAC), and in contentious-administrative litigation before the High Courts of Justice and the Audiencia Nacional. Our work in 2025 and 2026 has included the defence of Beckham Law beneficiaries against simulation and permanent establishment challenges, disputes concerning Modelo 720 and Modelo 721 reporting, and inheritance tax controversies arising from international succession.
For those seeking to enter Spain through one of its special regimes, to maintain residency through periods of regulatory change, or to defend established positions against the new generation of substance-based audits, we are pleased to discuss the matters set out above in confidence.
Read the full chapter on the Chambers and Partners website: Tax Controversy 2026 – Spain: Trends and Developments
