Banking Law and Infringement Litigation in Spain

1. Introduction

Banking law infringement litigation in Spain concerns disputes arising when a bank, credit institution, financial intermediary, director, or other regulated person is alleged to have breached banking, consumer-protection, prudential, contractual, or financial-market rules.

The expression “infringement litigation” is not a single statutory cause of action under Spanish law. It is better understood as a broad category covering litigation and administrative challenges arising from alleged breaches of banking regulation.

The Spanish framework operates at several levels:

Administrative enforcement, particularly proceedings brought by the Banco de España and other competent financial authorities.

Judicial review of administrative sanctions, generally before the contentious-administrative courts.

Civil litigation, including claims concerning unfair contractual terms, lack of transparency, restitution and damages.

EU-law litigation, especially where Spanish banking legislation implements or interacts with EU financial-services and consumer-protection law.

In sufficiently serious cases, conduct connected with banking activities may also give rise to criminal proceedings.

The principal prudential statute is Law 10/2014 of 26 June on the organisation, supervision and solvency of credit institutions (Ley 10/2014). It establishes a detailed infringement and sanctioning system. Article 91 divides regulatory infringements into very serious, serious and minor infringements.

2. Regulatory Structure

Spain's banking litigation framework combines Spanish legislation with directly applicable or implemented European Union rules.

Important sources include:

Law 10/2014 – regulates authorisation, supervision, solvency requirements and the sanctioning regime applicable to credit institutions.

Law 16/2011 on Consumer Credit Agreements – provides protections concerning consumer credit.

Law 5/2019 regulating Real Estate Credit Agreements – establishes significant information, transparency and conduct requirements for residential mortgage lending.

General Law for the Protection of Consumers and Users – particularly important where bank contracts contain allegedly unfair standard terms.

Law 7/1998 on General Contracting Conditions – relevant to standard-form banking contracts.

Law 39/2015 on Common Administrative Procedure – provides procedural rules relevant to administrative sanctioning proceedings.

Civil Procedure Act (Ley de Enjuiciamiento Civil) – governs much private banking litigation.

EU law is particularly important through Directive 93/13/EEC concerning unfair terms in consumer contracts and the extensive jurisprudence of the Court of Justice of the European Union.

3. Regulatory Infringements under Law 10/2014

Law 10/2014 establishes three principal categories.

Very serious infringements

Very serious infringements cover particularly significant regulatory violations. For example, carrying on the professional activity of accepting deposits or other repayable funds from the public without authorisation can constitute a very serious infringement.

Other breaches can involve matters such as authorisation requirements, prudential supervision, governance, capital requirements or failure to comply with regulatory obligations where the statutory conditions for classification as a very serious infringement are satisfied.

The classification matters because it determines the available sanctions.

For very serious infringements, Law 10/2014 permits substantial financial penalties. Depending upon the statutory method applicable to the case, a penalty may be calculated by reference to the benefit obtained from the infringement or the institution's annual turnover. The legislation currently provides, among its alternatives, for penalties reaching up to 10% of annual net turnover or specified statutory monetary limits in relevant circumstances.

Serious infringements

Serious infringements concern substantial violations that do not satisfy the statutory requirements for classification as very serious.

The legislation similarly permits significant financial sanctions. Current Article 98 includes alternatives based on benefits obtained and, in relevant cases, up to 5% of annual net turnover or statutory monetary limits.

Minor infringements

Less serious failures may be classified as minor infringements.

Although classified at the lowest level, they can still produce financial consequences. Article 99 provides mechanisms including penalties calculated by reference to the benefit obtained or, in relevant circumstances, up to 1% of annual net turnover or the applicable statutory ceiling.

4. Role of the Banco de España

The Banco de España has important supervisory and sanctioning responsibilities.

Under Article 90 of Law 10/2014, it has competence for the investigation and resolution of sanctioning proceedings falling within Title IV of that legislation and may impose the sanctions and administrative measures provided by law.

A sanctioning decision must be adequately reasoned. Law 39/2015 applies supplementarily to the exercise of the Banco de España's sanctioning powers.

This is important for infringement litigation because a regulated institution can challenge issues such as:

whether the alleged conduct actually occurred;

whether the conduct constitutes the alleged statutory infringement;

whether the authority followed the required procedure;

whether the institution's defence rights were respected;

whether responsibility was properly attributed;

whether the infringement was correctly classified;

whether the applicable limitation period had expired; and

whether the sanction was proportionate and legally justified.

A final administrative sanction can therefore become the subject of judicial review.

5. Publication and Judicial Challenges

Spanish banking enforcement also incorporates transparency requirements.

The Banco de España explains that, under Article 115.7 of Law 10/2014, sanctions and reprimands for serious and very serious infringements are generally published on its website after becoming final at the administrative level, subject to statutory exceptions concerning matters such as identification. Its published sanction records can also indicate whether judicial proceedings were brought against a sanction and their outcome.

This illustrates the distinction between:

Administrative finality – completion of the administrative process.

and

Judicial finality – completion of any subsequent court challenge.

A regulated entity can therefore dispute an administrative infringement finding through the mechanisms permitted under Spanish administrative and procedural law.

6. Civil Banking Infringement Litigation

Not every alleged banking-law violation results in an administrative penalty.

A large proportion of Spanish banking litigation concerns disputes between financial institutions and their customers.

Typical issues include:

mortgage clauses;

mortgage expenses;

floor clauses;

IRPH interest-reference clauses;

foreign-currency mortgages;

opening commissions;

transparency obligations;

unfair contractual terms;

restitution of improperly collected amounts; and

liability for inadequate information.

Spanish courts must frequently apply national contract and consumer law together with EU consumer law.

A critical distinction is therefore necessary:

A regulatory infringement and a civil-law finding that a contractual clause is unfair or non-transparent are not automatically the same thing.

The legal consequences also differ. Administrative proceedings may result in regulatory sanctions, while civil litigation may result in nullity of a contractual term, restitution, damages, costs or other private-law remedies.

7. Important Case Law

The following cases illustrate how infringement-related banking litigation operates in practice.

Case 1 — CJEU, Case C-415/11, Aziz v Caixa d'Estalvis de Catalunya, Tarragona i Manresa

Court: Court of Justice of the European Union
Judgment: 14 March 2013

Aziz is one of the foundational cases concerning Spanish mortgage enforcement and EU consumer protection.

The dispute concerned mortgage terms and the ability of Spanish procedural law to provide effective protection against unfair contractual clauses.

The CJEU concluded that Directive 93/13 required effective judicial protection against unfair terms. The judgment had major consequences for Spain's mortgage-enforcement framework because national procedural arrangements could not make the protection provided by EU consumer law ineffective.

Importance

Aziz established that procedural rules themselves can become crucial in banking litigation.

It strengthened the ability of Spanish courts to examine potentially unfair mortgage terms and demonstrated the supremacy and effectiveness requirements of EU consumer law.

Case 2 — CJEU, Joined Cases C-154/15, C-307/15 and C-308/15, Gutiérrez Naranjo and Others

Court: Court of Justice of the European Union
Judgment: 21 December 2016

These proceedings concerned Spanish mortgage floor clauses (cláusulas suelo).

Spanish jurisprudence had previously limited the temporal restitutionary consequences of declaring certain floor clauses unfair.

The CJEU held that EU consumer law prevented a national judicial limitation that deprived consumers of the full consequences normally resulting from a finding that an unfair contractual term was not binding.

Importance

The cases significantly affected Spanish banking litigation by strengthening the restitutionary consequences associated with unfair mortgage clauses.

They also demonstrated that domestic jurisprudential solutions must remain compatible with Directive 93/13.

Case 3 — CJEU, Case C-125/18, Gómez del Moral Guasch v Bankia

Court: Court of Justice of the European Union
Judgment: 3 March 2020

This case concerned a mortgage interest-rate clause linked to the IRPH reference index.

The CJEU examined whether such a contractual term was subject to transparency review under Directive 93/13 and what information was relevant to determining whether an average consumer could understand the economic consequences of the arrangement.

The judgment became an important part of the subsequent Spanish litigation concerning IRPH mortgages.

Importance

The decision confirmed the importance of meaningful transparency in banking contracts.

A term may be grammatically understandable but still require examination of whether the consumer was placed in a position to understand its economic implications.

Case 4 — Spanish Supreme Court, Judgment 42/2022

Court: Tribunal Supremo, Civil Chamber
Date: 27 January 2022

This litigation also concerned a mortgage loan whose variable interest rate was referenced to IRPH Entidades.

The borrowers sought nullity of the IRPH clauses and recalculation of the loan using Euribor.

The Supreme Court considered the developing CJEU jurisprudence concerning transparency and unfairness in IRPH contracts.

An important principle emerging from this line of authority is that lack of transparency does not automatically produce a finding of substantive unfairness. Where transparency is insufficient, the court may have to conduct the additional unfairness analysis required under EU consumer law.

Importance

The case demonstrates the distinction between:

incorporation of a contractual term;

transparency;

substantive unfairness; and

the consequences of nullity.

These concepts must not be treated as interchangeable in banking litigation.

Case 5 — Spanish Supreme Court, STS 3558/2020

Court: Tribunal Supremo, Civil Chamber
Date: 26 October 2020
ECLI: ECLI:ES:TS:2020:3558

The borrowers challenged several clauses in a mortgage loan alleging lack of transparency and unfairness.

The Supreme Court concluded, in relation to the contractual provisions before it, that the relevant amortisation and ordinary-interest provisions satisfied the incorporation requirements. The provisions appeared in the public deed and were considered grammatically comprehensible in the circumstances examined by the Court.

Importance

The decision illustrates an important limitation on banking infringement claims:

A consumer's challenge does not automatically succeed merely because a contractual provision is complex or financially significant.

The court must examine the particular clause, contractual documentation, information supplied and applicable legal test.

Case 6 — Spanish Supreme Court, STS 3705/2023

Court: Tribunal Supremo, Civil Chamber
Date: 20 September 2023
ECLI: ECLI:ES:TS:2023:3705

The litigation concerned the so-called “Hipoteca Tranquilidad.”

Customers sought nullity of several mortgage provisions and, alternatively, damages.

The Supreme Court concluded that the particular mortgage was not a complex financial product. It considered matters including the presentation of the applicable rates, the amortisation rules and the contractual explanation of ordinary interest and rejected the appeal on the facts before it.

Importance

The judgment demonstrates that transparency litigation is highly fact-specific.

The mere existence of sophisticated financial calculations does not necessarily establish a legal infringement. Courts examine whether contractual mechanisms and their financial consequences were sufficiently explained under the applicable legal standard.

Case 7 — Spanish Supreme Court, STS 3072/2025

Court: Tribunal Supremo, Civil Chamber
Date: 1 July 2025
ECLI: ECLI:ES:TS:2025:3072

This case involved litigation over an unfair mortgage floor clause and the consequences for legal costs.

The Supreme Court considered the effect of the lender's response to a consumer's pre-litigation demand.

The Court referred to its earlier plenary judgment 565/2024 and CJEU Case C-35/22. It emphasized that where established jurisprudence already identified the relevant clause as unfair, the lender's failure to take appropriate steps before litigation could remain relevant to the allocation of litigation costs.

Importance

Banking infringement litigation does not concern only whether a contractual provision is invalid.

It can also determine:

litigation costs;

consequences of pre-action conduct;

restitution; and

incentives for banks to resolve established consumer-law violations without unnecessary litigation.

Case 8 — Spanish Supreme Court, STS 3128/2025

Court: Tribunal Supremo, Civil Chamber
Date: 1 July 2025
ECLI: ECLI:ES:TS:2025:3128

This case concerned a foreign-currency/multicurrency mortgage.

Lower courts had declared the multicurrency provisions invalid. On cassation, however, the Supreme Court examined the information and simulations supplied by the bank.

The Court considered that the simulations adequately communicated relevant risks, including possible increases in instalments and outstanding principal resulting from currency appreciation and the consequences associated with changing currency.

Importance

The judgment shows why evidence is central to banking litigation.

The court may examine actual pre-contractual documentation rather than assuming either transparency or infringement merely from the nature of the banking product.

Case 9 — Spanish Supreme Court, Judgment 1590/2025 and Judgment 1591/2025

Court: Tribunal Supremo, Plenary Civil Chamber
Date: November 2025

These important judgments revisited IRPH mortgage litigation after subsequent CJEU judgments, including Case C-265/22 and Case C-300/23.

The Supreme Court explained that there is no single automatic answer regarding transparency and unfairness of an IRPH clause. The validity of the clause depends on the particular circumstances of the loan and the facts established in the litigation.

Judgment 1590/2025 provided guidance concerning transparency, while Judgment 1591/2025 addressed the subsequent unfairness assessment where transparency is not satisfied.

Importance

These decisions reinforce a central principle of Spanish banking litigation:

Individual examination of the transaction matters.

Courts should not simply declare every clause using a particular reference index valid or invalid without considering the legally relevant circumstances.

Case 10 — Spanish Supreme Court, STS 4955/2025

Court: Tribunal Supremo, Civil Chamber
Date: 12 November 2025
ECLI: ECLI:ES:TS:2025:4955

This dispute concerned an opening commission of 2.17% of the mortgage principal.

The Supreme Court referred to CJEU Case C-565/21 and its own Judgment 816/2023. It reiterated that the validity of an opening-fee clause cannot be determined through an entirely automatic rule and requires examination of the particular circumstances.

In this case, the Court regarded the 2.17% commission as disproportionate in relation to the loan amount and upheld the finding that the clause was unfair.

Importance

The case demonstrates how proportionality and the actual economic burden placed on the consumer can become relevant in infringement-related contractual litigation.

8. Procedural Questions in Infringement Litigation

Standing

The claimant must have legal standing to bring the relevant proceedings.

Depending on the type of litigation, this might be:

a consumer;

borrower;

investor;

regulated institution;

shareholder;

consumer association; or

another person whose legally protected interests are affected.

Administrative sanctioning proceedings operate differently because the regulatory authority initiates enforcement under its statutory powers.

Evidence

Evidence commonly includes:

loan agreements;

mortgage deeds;

pre-contractual information;

correspondence;

risk warnings;

simulations;

account statements;

internal banking documentation where legally obtainable;

regulatory decisions; and

expert financial evidence.

The importance of evidence is particularly clear from the Supreme Court's multicurrency-mortgage jurisprudence, where information and simulations provided to the borrower may materially affect the transparency assessment.

9. Limitation Periods and Restitution

Limitation is another major source of Spanish banking litigation.

An important distinction exists between an action seeking a declaration that an unfair contractual term is void and an action seeking repayment of money paid pursuant to that term.

Recent Supreme Court jurisprudence on mortgage expenses has considered the CJEU's judgments of 25 April 2024.

The Supreme Court's plenary Judgment 857/2024 of 14 June 2024 established, subject to the particular circumstances and proof that the consumer possessed earlier knowledge, that the starting point for limitation of the restitution claim is generally connected with the final judgment declaring the expenses clause void.

This approach has continued to influence later Supreme Court judgments concerning mortgage-expense restitution.

The issue illustrates the interaction among:

invalidity → restitution → limitation → effective consumer protection.

10. Remedies

Different remedies apply according to the type of infringement.

Administrative remedies

Regulators may impose:

financial penalties;

public or private reprimands;

orders requiring cessation of unlawful conduct;

governance-related measures; and

other measures authorised by banking legislation.

Law 10/2014 expressly provides substantial penalties for serious and very serious infringements.

Civil remedies

A court may, depending upon the cause of action:

declare a contractual provision void;

prevent continued application of an unfair term;

order restitution;

award damages where the requirements for liability are established;

require recalculation of contractual obligations; or

make an appropriate costs order.

The precise remedy depends on the substantive infringement and procedural route.

11. Relationship Between Spanish and EU Law

EU law has had an especially strong influence on Spanish banking litigation.

Spanish courts must interpret national rules consistently with EU legislation and comply with binding CJEU interpretations.

This has been particularly visible in litigation involving:

mortgage floor clauses;

IRPH;

mortgage expenses;

acceleration clauses;

consumer procedural protection;

limitation periods; and

restitution.

Cases such as Aziz, Gutiérrez Naranjo and Gómez del Moral Guasch demonstrate that EU consumer law can require changes not only to the interpretation of substantive contractual rules but also to national procedural arrangements.

Consequently, infringement litigation in Spanish banking law cannot be analysed solely by examining Spanish legislation.

12. Practical Litigation Structure

A banking infringement dispute in Spain can normally be analysed through the following sequence:

First: Identify the allegedly violated rule.

Second: Determine whether the issue is regulatory, contractual, consumer-related, prudential, market-related or potentially criminal.

Third: Identify the competent authority or court.

Fourth: establish whether the claimant has standing.

Fifth: determine the applicable limitation rules.

Sixth: analyse the evidence demonstrating the alleged infringement.

Seventh: consider relevant Spanish and CJEU jurisprudence.

Eighth: determine whether EU law affects the interpretation of the Spanish provision.

Ninth: establish causation where damages are claimed.

Tenth: determine the appropriate remedy.

This method prevents an important analytical error: assuming that every breach of a regulatory requirement automatically creates a private damages action.

Whether private liability exists depends on the legal rule breached, the purpose of that rule, the applicable cause of action, causation, loss and the remedies recognised by Spanish and EU law.

13. Key Principles Emerging from the Case Law

Several general principles can be identified.

Transparency is substantive

Banking information must often enable a consumer to understand the economic consequences of an important contractual provision rather than merely allowing the consumer to read its words.

Lack of transparency and unfairness are distinct

As the IRPH jurisprudence demonstrates, failure of transparency does not invariably mean that the contractual term is automatically substantively unfair. The appropriate unfairness assessment may still be necessary.

Each contract may require individual assessment

The Supreme Court's recent IRPH and opening-commission jurisprudence emphasizes the importance of the circumstances of the individual transaction.

Evidence supplied before contracting matters

Risk simulations, contractual explanations and pre-contractual information can materially influence the result of litigation, as illustrated by the Supreme Court's 2025 multicurrency-mortgage judgment.

EU effectiveness is fundamental

Spanish procedural and substantive rules must preserve the effectiveness of rights granted by EU law.

Regulatory and private liability should be separated

A bank may face an administrative investigation without necessarily becoming civilly liable to every affected person. Conversely, a consumer may obtain civil relief concerning an unfair contractual term even where the case does not involve a regulatory sanction.

Conclusion

Banking Law and Infringement Litigation in Spain is a broad field combining prudential regulation, administrative enforcement, contract law, consumer protection, civil procedure and European Union law.

Law 10/2014 provides the central banking supervisory and sanctioning framework and classifies infringements as very serious, serious or minor. The Banco de España has significant enforcement authority, while its sanctioning decisions remain subject to the safeguards of administrative procedure and, where applicable, judicial review.

Private banking litigation follows a different but interconnected route. Spanish courts and the CJEU have developed extensive jurisprudence concerning unfair mortgage terms, floor clauses, IRPH, multicurrency mortgages, opening commissions, mortgage expenses, restitution and transparency.

The major cases—including Aziz (C-415/11), Gutiérrez Naranjo (Joined Cases C-154/15, C-307/15 and C-308/15), Gómez del Moral Guasch (C-125/18), STS 3558/2020, STS 42/2022, STS 3705/2023, STS 3072/2025, STS 3128/2025, STS 1590/2025, STS 1591/2025 and STS 4955/2025—show that Spanish banking infringement litigation increasingly depends on an integrated analysis of national banking legislation, contractual evidence, consumer-protection principles and binding EU law.

Accordingly, a sound legal analysis should identify the exact infringement, distinguish regulatory enforcement from private liability, determine the appropriate procedural route, examine the evidence and limitation rules, and then apply both Spanish and relevant EU jurisprudence before determining the available remedy.