Defending Spanish tax audits: 2026 guide for subsidiaries of foreign groups

Notification of the opening of audit proceedings always lands at the wrong moment. For a Spanish subsidiary of an international group, the problem multiplies: the parent company demands explanations, statutory deadlines start running on day one, and the documentation the AEAT (Spanish tax authority) requests — comparables, master file, intra-group contracts, residence certificates — is rarely sitting ready in a drawer.

This guide is aimed at CFOs, controllers and tax directors of Spanish subsidiaries of foreign groups. It covers how the inspección (tax audit) procedure actually works in 2026, which areas the AEAT is targeting under the Plan de Control Tributario (Annual Tax Control Plan) published on 11 March 2026, the statutory deadlines you need to internalize, and the critical decisions a finance team must take in the first 48 hours after receiving the opening communication.

When does the AEAT open an audit on a foreign-owned subsidiary?

A Spanish subsidiary of an international group enters the AEAT’s radar through a combination of factors that the risk-selection system cross-checks automatically:

• Operating margin significantly below Spanish sector comparables, sustained over several financial years.
• High payments to related entities for royalties, interest, management fees or technical services.
• Recurring losses while the international group consolidates profits.
• Transactions with jurisdictions on the Modelo 232 list or with low taxation.
• Application of the dividend participation exemption under art. 21 LIS (Spanish Corporate Income Tax Act) on structures with an intermediate holding lacking obvious substance.
• Régimen Beckham (Spanish inbound expatriate regime) applied to executives without alignment with DGT (Directorate-General for Taxation) criteria.
• Discrepancies between Modelo 296 (non-resident withholding tax) and actual payments.
• In 2026, anomalies detected via DAC8 (crypto-assets) or between Modelo 240/241 (Pillar 2).

The 2026 Control Plan expressly states that AI is used to automatically identify deviations in the profitability of Spanish subsidiaries by comparing them against global databases in real time. This means risk is assessed before the file is opened, and the audit arrives with a thesis already formed. The “explanation” phase of the procedure serves more to confirm the thesis than to open neutral investigation.

Procedimiento de gestión vs inspección: which is which

The Spanish tax authorities can review tax filings via two different routes, with different deadlines and powers:

Procedimiento de comprobación limitada (limited verification procedure — Gestión)

Run by the Tax Management Office (Gestión Tributaria). It is limited to checking specifically what is set out in the opening notice (a particular form, a deduction, an assessment), without examining commercial accounting records. Maximum duration: 6 months. Actions are documented through formal requests, and adjustments are proposed via a draft assessment.

Procedimiento inspector (full audit — Inspección)

Run by the Inspection Department. It carries broad powers: examining accounting records, books and commercial registers; cross-checking data; auditing transfer pricing; requesting information from third parties. General duration: 18 months, extendable to 27 in consolidated groups or for taxpayers with high turnover.

For subsidiaries of foreign groups, the standard practice is the full audit: transfer pricing, economic substance and the application of exemptions require the depth that only the inspection procedure allows.

Phases of the audit procedure

Phase 1 — Opening (notification)

The audit starts with a comunicación de inicio (formal opening notice), notified through official channels. From the date of notification, the 18/27-month clock starts running. The notice indicates:

• Tax periods and items under audit (scope).
• Whether the audit is general or partial in scope.
• Documentation required for the first appearance.

Critical decision in the first 48 hours: review the temporal and material scope, identify whether there is a risk of the scope being extended to other tax years, and assess whether to anticipate a voluntary regularization (art. 27 LGT, reduced surcharges).

Phase 2 — Verification actions

The inspector requests documentation, issues formal information requests, examines the accounts, and cross-checks data with information held in AEAT and third-party databases. The taxpayer signs diligencias (formal minutes) documenting each appearance.

Two critical points:

• The facts recorded in a diligencia are presumed to be true (art. 107 LGT). Do not sign anything that is not accurate. Clarify any discrepancies before signing.
• The burden of proof for exemptions, deductions and tax credits lies with the taxpayer (art. 105 LGT). The inspector does not need to prove that the exemption does not apply — the taxpayer must prove that it does.

Phase 3 — Hearing trámite and proposal

Before closing, the audit team issues a propuesta de regularización (proposed assessment). The taxpayer is granted access to the file and has 10 days (extendable) to file written submissions.

This phase is the last opportunity to add further evidence, case law, DGT doctrine and technical arguments before the final assessment is issued.

Phase 4 — Acta and assessment

Audit proceedings end in an acta (audit report), which can be:

• Acta de conformidad (audit report signed in agreement): the taxpayer accepts the assessment. The penalty is reduced by 30% (plus an additional 25% if paid within the voluntary period and no appeal is filed).
• Acta de disconformidad (audit report signed in disagreement): the taxpayer disputes the assessment. The audit team issues its proposal and the taxpayer can file submissions. The assessment is then issued.
• Acta con acuerdo (audit report by agreement): an exceptional procedure for indeterminate legal concepts (art. 155 LGT). Higher penalty reductions in exchange for waiving the right to appeal.

Phase 5 — Appeals

Two incompatible routes are available against the assessment:

• Recurso de reposición (administrative appeal) before the body that issued the assessment (15 days). It is optional.
• Reclamación económico-administrativa (economic-administrative claim) before the TEAR/TEAC (Regional/Central Economic-Administrative Tribunal) (1 month). It is mandatory before going to the courts.

After exhausting the economic-administrative track, the taxpayer can file a contentious-administrative appeal before the TSJ (High Court of Justice) and, where applicable, a cassation appeal before the Tribunal Supremo (Spanish Supreme Court).

Key deadlines you should internalize

The 4-year statute of limitations is computed day-to-day, in line with consolidated Tribunal Supremo doctrine. A formal opening notification interrupts the limitation period and resets the clock. This is why notifications often arrive at year-end: the AEAT seeks to interrupt the limitation period before the oldest year within scope expires.

Areas the AEAT is targeting in 2026

Under the 2026 Plan de Control Tributario and our experience with recent files, the priority focus areas for subsidiaries of foreign groups are:

Transfer pricing and related-party transactions

This is the front line of fire. The audit team checks that the declared profitability of the Spanish subsidiary is consistent with the functions performed and risks assumed, benchmarked against commercial databases (TP Catalyst, Amadeus). Mandatory documentation: master file, local file, country-by-country report (Modelo 231), Modelo 232 (related-party transactions).

Recurring issues in 2026:

• Cost-plus margins in intra-group service subsidiaries: the AEAT challenges margins below 5% absent a functional justification.
• Distributors with net margins below the interquartile range of independent comparables.
• Royalties paid to the parent without a comparability study.
• Management services whose value added is challenged (the “shareholder activity” rule under Chapter VII of the OECD Guidelines).

Economic substance and ATAD 3

European holding companies without substance (empty offices, no employees, no real decision-making) are systematically challenged. The ATAD 3 Directive (UNSHELL), pending final approval but already informing AEAT criteria, requires minimum substance to access directive and treaty benefits.

Participation exemption on dividends and capital gains (art. 21 LIS)

The 2026 Plan expressly cites “artificial structures designed to achieve undue non-taxation through the exemption on dividends and capital gains”. Recent reorganizations involving intermediate holding companies must be supported by valid economic motive.

Régimen Beckham (inbound expatriate regime)

Verification that the relocation is genuine, that the activity is effectively performed in Spain, that the employment contract is genuine, and that the conditions of art. 93 LIRPF (Personal Income Tax Act) are met. Cases of executives benefiting from the regime but with limited physical presence in Spain are a recurring focus area.

Pillar 2 / top-up tax

From 2026, groups with consolidated turnover above EUR 750 million must file Modelo 240 and Modelo 241. The AEAT will cross-check this information with Modelo 232 and Modelo 200 (Spanish corporate income tax return) to identify aggressive tax planning.

Non-resident income tax (IRNR) and withholding

Correct application of reduced treaty rates (valid residence certificates), parent-subsidiary exemption (substance, beneficial ownership), and reconciliation between Modelo 216 and Modelo 296.

Defense strategies: three paths

Path A — Acceptance with conformity

Where the proposed assessment is reasonable and the applicable penalty is at the minimum level, signing an acta de conformidad reduces the penalty by 30% on top of the 25% reduction for payment within the deadline and no appeal. Total: up to 55% reduction on the base penalty.

Advisable when: the cost of litigating exceeds the tax debt, there is no clear favorable case law precedent, and reputational damage vis-à-vis the group is contained.

Path B — Disagreement and technical submissions

The taxpayer signs an acta de disconformidad, files technical submissions within the deadline, awaits the assessment, and prepares the economic-administrative claim.

Advisable when: there is favorable DGT doctrine or case law, the proposed assessment contains factual or legal errors, and the amount at stake justifies the professional cost of the file.

Path C — Acta con acuerdo (art. 155 LGT)

For items where there is legitimate interpretive divergence (valuations, estimates), the taxpayer and the audit team can sign an acta con acuerdo, with a 65% penalty reduction in exchange for waiving the right to appeal. It is a rarely used mechanism but useful in specific cases.

Most common mistakes

1. Waiting until the proposal is issued to start building the defense. Strategy is decided at the first appearance. Late efforts rarely make up the lost ground.
2. Signing diligencias without reading them. The recorded facts are presumed true. They are the foundation upon which the entire assessment is built.
3. Not requesting suspension when the requested documentation is genuinely complex to assemble. The 60 days are cumulative across the whole procedure — use them strategically.
4. Not coordinating with the group. Audits of subsidiaries of foreign groups typically require documentation and evidence held at the parent. An international team must be involved from day one.
5. Underestimating the 18/27-month clock. If the audit exceeds the deadline, the assessment is procedurally defective and default interest stops accruing.