Tax Reform & Pillar Two in Spain: 2026 Update

Tax reform and Pillar Two in Spain represent one of the most significant shifts in Spanish corporate taxation in a generation. Spain has enacted legislation implementing the OECD';s global minimum tax framework, aligning with EU Directive 2022/2523 and bringing large multinational groups operating in Spain into a new compliance reality. The 15% effective tax rate floor applies to groups with consolidated revenues above EUR 750 million, and the rules carry immediate consequences for tax planning, deferred tax accounting and intercompany structures. This guide covers the legal framework, the mechanics of the top-up tax, recent legislative developments, compliance obligations, and the practical implications for international businesses with a Spanish footprint.

Spain transposed EU Directive 2022/2523 - the so-called Minimum Tax Directive - through Royal Decree-Law 8/2023 and subsequently through the formal Ley de Impuesto Complementario, which established the Complementary Tax (Impuesto Complementario) as a standalone levy within the Spanish tax system. The law was published in the Official State Gazette (Boletín Oficial del Estado, BOE) and applies to fiscal years beginning on or after 1 January of the relevant implementation year.

The Spanish legislature chose to implement all three charging mechanisms permitted under the Directive. The Income Inclusion Rule (IIR) allows Spain to tax a Spanish parent entity on the low-taxed income of its foreign subsidiaries. The Undertaxed Profits Rule (UTPR) operates as a backstop, allowing Spain to collect top-up tax where a foreign parent jurisdiction has not applied the IIR. The Qualified Domestic Minimum Top-up Tax (QDMTT) ensures that Spain itself collects any top-up tax due on Spanish-source income before a foreign jurisdiction can do so under the IIR or UTPR.

The Spanish Tax Agency (Agencia Tributaria) is the competent authority for administration, assessment and enforcement of the Complementary Tax. The rules interact with the existing Corporate Income Tax Law (Ley del Impuesto sobre Sociedades, LIS), but the Complementary Tax is computed separately and filed on a dedicated return.

The global minimum tax rules in Spain apply exclusively to constituent entities that are members of a multinational enterprise (MNE) group or a large-scale domestic group with consolidated annual revenues of EUR 750 million or more in at least two of the four fiscal years immediately preceding the current year. This threshold mirrors the OECD GloBE Model Rules and the EU Directive precisely.

Entities below this revenue threshold are entirely outside the scope of the Complementary Tax. However, smaller subsidiaries of large groups are still constituent entities and must provide data to the group';s filing entity. A common mistake among mid-size Spanish subsidiaries is assuming that because they themselves are small, the rules do not apply to them at all - in practice, they remain within scope as constituent entities of a qualifying group.

Excluded entities under the Spanish law include government entities, international organisations, non-profit organisations, pension funds and certain investment funds that qualify as Ultimate Parent Entities. Real estate investment vehicles meeting specific conditions may also be excluded. These exclusions follow the GloBE Model Rules closely, but the precise conditions must be verified against the Spanish implementing text, as domestic drafting choices can introduce nuances.

The QDMTT applies to all constituent entities located in Spain, regardless of where the Ultimate Parent Entity is resident. This means that even a Spanish subsidiary of a US, UK or Asian group is subject to the Spanish QDMTT if the group meets the revenue threshold and the Spanish entities'; effective tax rate falls below 15%.

The effective tax rate (ETR) under GloBE is not the same as the statutory corporate income tax rate. Spain';s headline corporate income tax rate is 25%, which in most cases produces an ETR well above 15%. However, the GloBE ETR is computed jurisdiction-by-jurisdiction using a specific formula: adjusted covered taxes divided by GloBE income or loss for the jurisdiction.

Adjustments to covered taxes include deferred tax liabilities and assets, uncertain tax positions, and taxes paid in prior years. Adjustments to income include stock-based compensation, pension accruals, and certain intragroup transactions. The result is that a Spanish entity with significant tax incentives, accelerated depreciation, R&D credits or patent box regimes may find its GloBE ETR falling below 15% even though it pays Spanish corporate tax at the standard rate.

Spain';s patent box regime (reducción de rentas procedentes de determinados activos intangibles under Article 23 LIS) and its R&D tax credit (deducción por actividades de investigación y desarrollo e innovación tecnológica) are among the incentives most likely to reduce the GloBE ETR for Spanish entities. Groups relying heavily on these incentives should model their GloBE ETR carefully.

The top-up tax is the amount needed to bring the ETR to exactly 15%. It is computed at the jurisdictional level, not entity by entity. If the Spanish jurisdiction';s blended ETR across all constituent entities is above 15%, no top-up tax is due in Spain under the QDMTT, even if individual entities have lower ETRs. This blending effect can work in favour of groups with mixed profiles in Spain.

The Substance-Based Income Exclusion (SBIE) reduces GloBE income by a fixed percentage of eligible payroll costs and tangible asset carrying values. This exclusion rewards genuine economic substance and is particularly relevant for manufacturing, logistics and service companies with significant Spanish headcount and fixed assets. In practice, founders should consider whether their Spanish operations qualify for meaningful SBIE relief before concluding that a top-up tax liability exists.

Beyond Pillar Two, Spain has been engaged in a broader corporate tax reform agenda. The Spanish government has proposed amendments to the LIS addressing interest limitation rules under the Anti-Tax Avoidance Directive (ATAD), controlled foreign corporation (CFC) rules, and hybrid mismatch arrangements. These reforms interact with the GloBE framework and can affect the covered taxes calculation.

A significant recent development is Spain';s approach to deferred tax assets (DTAs) arising from the Complementary Tax itself. The Spanish implementing law includes specific provisions on how GloBE deferred tax assets and liabilities are recognised and whether they qualify as covered taxes in future periods. This is a technically complex area where accounting treatment under IFRS or Spanish GAAP can diverge from the GloBE tax treatment.

Spain has also clarified its position on the transitional safe harbours introduced by the OECD. The Transitional Country-by-Country Reporting (CbCR) Safe Harbour allows groups to use their existing CbCR data to determine whether a simplified ETR test, a routine profits test or a de minimis test is met. If any of these tests is satisfied for a jurisdiction, the top-up tax for that jurisdiction is deemed to be zero for the transitional period. Spain has confirmed that it will apply these safe harbours, providing significant compliance relief for groups in the initial years of implementation.

The OECD continues to issue administrative guidance on GloBE, and Spain has committed to incorporating agreed guidance into its domestic framework. Groups should monitor updates from the Agencia Tributaria and the OECD';s Inclusive Framework, as guidance on specific topics - including the treatment of equity method income, insurance companies and investment funds - continues to evolve.

If you are assessing how these developments affect your group';s Spanish structure, we can help you map the exposure and identify available reliefs. Contact us at info@vlolawfirm.com.

The primary compliance mechanism under the Spanish Complementary Tax is the GloBE Information Return (GIR). Spain has adopted the OECD';s standardised GIR format, which requires detailed information on each constituent entity, its jurisdiction, its GloBE income or loss, its covered taxes, and the computation of the ETR and top-up tax. The GIR must be filed within 15 months of the end of the fiscal year for the first year of application, and within 18 months for subsequent years.

The filing obligation can be centralised. If the Ultimate Parent Entity is resident in a jurisdiction that has a Qualifying Competent Authority Agreement (QCAA) with Spain, the UPE can file the GIR on behalf of all constituent entities, and Spain will receive the information through automatic exchange. If no such agreement exists, each Spanish constituent entity must file locally. A common mistake is assuming that a non-EU UPE';s local filing automatically satisfies the Spanish obligation - this is only the case where a valid QCAA is in place.

The Complementary Tax return itself is separate from the standard corporate income tax return (Modelo 200). Spain has introduced a dedicated return for the QDMTT and the IIR. Payment of the Complementary Tax follows the same general timeline as the corporate income tax, with instalments required during the fiscal year once the liability is established.

Penalties for non-compliance with the GIR filing obligation can be substantial. The Spanish penalty regime for information returns is based on the number of data items omitted or incorrectly reported, and can escalate quickly for large groups with many constituent entities. Groups should ensure that their data collection processes are robust and that intercompany agreements are consistent with the information reported in the GIR.

Transfer pricing documentation requirements under Spanish law (Royal Decree 634/2015, which implements the LIS transfer pricing rules) remain fully applicable alongside the GloBE framework. The two sets of rules are independent, but inconsistencies between transfer pricing positions and GloBE income calculations can attract scrutiny from the Agencia Tributaria.

For a US-headquartered group with a Spanish subsidiary engaged in software development and holding significant R&D tax credits, the GloBE ETR for Spain may fall below 15% even though the subsidiary pays corporate tax at the standard rate. The group';s US parent would first look to the IIR to collect the top-up tax. However, because Spain has enacted a QDMTT, Spain collects the top-up tax first, and the US parent';s IIR liability is reduced accordingly. The practical result is that the top-up tax is paid in Spain rather than in the US, which may affect the group';s overall cash tax position and its ability to use foreign tax credits.

For a European holding group with its UPE in Luxembourg and operating subsidiaries across Spain, France and Germany, the blending of ETRs within each jurisdiction is critical. If the Spanish entities as a whole have a GloBE ETR above 15%, no Spanish QDMTT is due, even if individual entities benefit from incentives. The Luxembourg UPE applies the IIR to any low-taxed jurisdictions in the group. Spain is unlikely to be a low-taxed jurisdiction for most standard operating businesses, but the analysis must be done entity by entity and jurisdiction by jurisdiction each year.

Many multinationals underestimate the data burden of GloBE compliance. The GIR requires granular financial data that is often not captured in existing ERP systems or statutory accounts. Groups with decentralised finance functions or multiple local GAAP adjustments face particular challenges in producing consistent GloBE data across jurisdictions. Early investment in data infrastructure and process design is a practical necessity, not an optional enhancement.

A non-obvious requirement is the interaction between the GloBE rules and Spain';s existing controlled foreign corporation (CFC) regime under Article 100 LIS. Where a Spanish parent has applied CFC charges to income of a low-taxed foreign subsidiary, those CFC charges may qualify as covered taxes for GloBE purposes, potentially reducing the top-up tax. However, the qualification conditions are specific and must be verified carefully.

What is the difference between the QDMTT and the IIR in Spain?

The Qualified Domestic Minimum Top-up Tax (QDMTT) is a Spanish domestic charge on the low-taxed income of entities located in Spain. It is collected by the Agencia Tributaria before any foreign jurisdiction can apply its own top-up tax under the Income Inclusion Rule (IIR). The IIR, by contrast, is applied by a parent entity';s jurisdiction to the low-taxed income of its subsidiaries in other countries. Spain applies both rules: the QDMTT protects Spanish taxing rights over Spanish-source income, while the IIR allows Spanish parent entities to top up the tax on their low-taxed foreign subsidiaries. For most standard Spanish operating companies with an ETR above 15%, neither charge will apply, but the distinction matters for groups with significant tax incentives or unusual structures.

How long does it take to comply, and what does it cost?

The timeline for GloBE compliance depends heavily on the complexity of the group. For a group with a small number of Spanish entities and straightforward financials, preparing the GIR and the Complementary Tax return may take several weeks of professional time. For a large group with many Spanish constituent entities, multiple GAAP adjustments and significant tax incentives, the process can take several months and require dedicated project management. Professional fees for GloBE compliance in Spain typically start from the low tens of thousands of EUR for simpler structures and rise significantly for complex groups. The first year of compliance is invariably the most expensive, as data infrastructure and processes must be built from scratch. Subsequent years benefit from established workflows, but ongoing monitoring of OECD guidance and Spanish legislative updates adds a recurring advisory cost.

Can Spanish tax incentives still be used effectively under Pillar Two?

Yes, but their value must be reassessed in light of the GloBE framework. Spain';s R&D tax credit and patent box regime remain available under domestic law and can still reduce the Spanish corporate income tax liability. However, if their use causes the GloBE ETR for Spain to fall below 15%, a QDMTT liability arises that partially offsets the benefit of the incentive. The net benefit depends on the group';s specific ETR position, the availability of the SBIE, and whether other Spanish entities in the group have higher ETRs that can be blended. In many cases, the incentives remain valuable even after GloBE, particularly for groups with substantial Spanish payroll and tangible assets that generate meaningful SBIE relief. A careful modelling exercise is essential before concluding that an incentive has lost its value.

Spain';s implementation of Pillar Two marks a structural change in the corporate tax landscape for large multinationals. The QDMTT, IIR and UTPR are now live domestic rules, not future proposals. Groups with a Spanish presence above the EUR 750 million threshold must assess their GloBE ETR, build compliant data processes and file the GIR on time. Tax incentives remain available but require careful modelling. The interaction with existing Spanish corporate tax rules adds further complexity that rewards early preparation.

VLO Law Firms advises international clients on tax reform and Pillar Two matters in Spain. We can assist with GloBE ETR modelling, QDMTT analysis, GIR preparation, interaction with Spanish corporate income tax rules, and coordination with group tax functions across jurisdictions. To request a consultation, contact: info@vlolawfirm.com