How far may a professional limit their own liability? Exclusion clauses, fees and freedom of contract after Supreme Court Judgment 949/2026
Judgment 949/2026 of 18 June of the “Tribunal Supremo” —Spain's Supreme Court, hence STS— examines a professional services contract entered into by a law firm which capped the professional's maximum liability at the amount of the fees received. The Chamber declares the clause void, not because it amounted to standard terms used against a consumer, but because it is incompatible with the structural principles of the contract and with the compensatory function of contractual liability, even in the context of a negotiated contract between professionals. The Court questions that the provider itself should be able to determine its liability ceiling indirectly through its fees, that the cap should operate regardless of the seriousness of the breach and that it may end up depriving the duty to compensate of all content. Although the case concerns lawyers, the doctrine may be extended to auditors, tax advisers, engineers, consultants and other providers of professional services.
1.The case: loss of chance at an auction and a clause capping liability at the fees
STS 949/2026 starts from a professional services contract entered into between a foundation and a law firm for the firm to act at a judicial auction of a property of which the foundation was already a co-owner of a very high percentage. The board of trustees had authorised the lawyer to bid up to a given financial limit, but he decided not to exhaust that bidding margin, taking the view that the price was being driven up artificially. The property was ultimately awarded to a third party for an amount below the authorised maximum, and the foundation sued the lawyer, the firm and their insurers for professional negligence, claiming the loss of the opportunity to acquire 100 per cent of the property.
The services contract contained two relevant clauses. One capped the firm's maximum liability at the amount of the fees received for the particular engagement. The other laid down a one-year time bar for bringing a liability claim, running from completion of the work. Both the “Juzgado de Primera Instancia” —the court of first instance— and the “Audiencia Provincial” —the provincial appeal court— partly upheld the claim, finding professional negligence in the lawyer's conduct and declaring the limitation of liability clause void because it created an unjustified imbalance between the parties and distorted the compensatory function of the contract. The time-bar clause was construed as meaning that the out-of-court claim made within the year satisfied its requirement, so that it was unnecessary to enter into the debate as to its validity.
The Supreme Court dismisses the defendants' cassation appeal and upholds the nullity of the limitation of liability clause, laying down a far-reaching doctrine on the limits of freedom of contract in shaping professional liability.
2.Freedom of contract, art. 1255 CC and the limits on limiting liability
The starting point of STS 949/2026 is the principle of freedom of contract laid down in article 1255 of the “Código Civil” —the Spanish Civil Code— which allows contracting parties to agree such covenants, clauses and conditions as they see fit, provided that they are not contrary to the law, to morality or to public policy. Contractual liability, governed by articles 1101 et seq., performs an essentially compensatory function: to make good the loss caused by the breach, covering both actual loss and loss of profit, within the limits of foreseeability and good faith.
The Supreme Court accepts that, in contracting between professionals, limitation of liability clauses may be agreed, provided that they respect the limits of article 1255 and do not deprive the duty to compensate of all content. The question is therefore not confined to a review of standard terms used against consumers, but extends to a review of compatibility with the structure and function of the contract, even where the clause has been negotiated between parties of similar bargaining power.
The Chamber takes the view that a clause capping the professional's maximum liability at the amount of the fees received infringes those limits where, by reason of its specific configuration, it distorts the compensatory function of contractual liability. The problem is not merely quantitative but structural: if the potential loss flowing from professional negligence may far exceed the fees, setting such a low ceiling turns liability into something merely symbolic and deprives the client of adequate redress.
3.Criticism of self‑determination of the liability ceiling and of indifference to the seriousness of the breach
One of the most significant aspects of STS 949/2026 is its criticism of the fact that the service provider itself may indirectly determine its liability ceiling by setting its fees. The clause under examination tied maximum liability to the amount of the fees invoiced for the engagement, so that the professional, in setting their fees, was also setting the limit of their liability. The Court holds that this self‑determination of the liability ceiling is incompatible with contractual good faith and with the minimum balance that must exist between the parties' obligations.
The Chamber stresses that the cap operated regardless of the seriousness of the breach. The clause drew no distinction between minor, serious or wilful breaches, nor between reasonable errors of judgment and gross negligence. In every case liability was limited to the same amount, which is particularly problematic where the loss caused may be very high, as in transactions of high economic value or in situations in which the loss of chance has a significant financial impact.
The Court emphasises that a clause limiting liability to the fees, without modulating it according to the seriousness of the breach or the potential loss, may end up distorting the compensatory function of the contract. Contractual liability ceases to be an effective mechanism of redress and an incentive to diligent performance, and becomes a cost that is bearable and foreseeable for the professional, who can internalise it as part of their pricing structure.
4.Nullity of the clause and the compensatory function of contractual liability
STS 949/2026 declares the limitation of liability clause void, not for breach of specific rules on consumers or standard terms, but because it runs counter to the general principles of contract and to the compensatory function of liability. The Chamber relies on articles 1255 and 1256 of the Civil Code, the latter prohibiting the validity and performance of contracts from being left to the discretion of one of the contracting parties. A clause which allows the professional to set their liability ceiling indirectly through their fees and which reduces compensation to a derisory amount in relation to the potential loss comes close to leaving performance of the duty to compensate to the debtor's discretion.
The Court rejects the contention that wilful misconduct must be established in order to declare the clause void. Article 1102 CC, which prohibits the advance waiver of the right of action to claim liability for wilful misconduct, does not exhaust the cases in which exclusion or limitation of liability clauses may be invalid. Nullity may also follow from a breach of mandatory rules or of the structural principles of the contract, such as good faith, the minimum balance between the parties' obligations and the compensatory function of liability.
The consequence of nullity is that the clause is treated as not written, and the professional's liability is governed by the general rules of the Civil Code and by the content of the contract, without the artificial ceiling imposed by the stipulation. In the particular case, the Court upholds the order to compensate the loss of chance suffered by the foundation, calculated by reference to the difference between the reasonable value of the frustrated transaction and the resulting financial position.
5.Extension of the doctrine to other professionals: auditors, advisers, engineers, consultants
Although STS 949/2026 concerns a services contract of a law firm, the doctrine it lays down may readily be extended to other providers of professional services, such as auditors, tax advisers, engineers, architects, consultants or expert witnesses. In all these fields it is common to find clauses limiting the professional's liability to a multiple of the fees, to a fixed sum or to the limits of the civil liability insurance policy.
The judgment does not rule out the possibility of agreeing limits on liability, but it requires that they respect the compensatory function of the contract and do not turn liability into something merely symbolic. A reasonable limit may take into account the nature of the service, the economic value of the transaction, the cover afforded by the civil liability insurance and the proportionality between the risk assumed and the remuneration. What STS 949/2026 rejects is the setting of a ceiling so low and so directly tied to the fees that it deprives the duty to compensate of all content.
The doctrine also has implications for the drafting of professional liability insurance policies. Insurers usually set limits of cover per claim and per policy year, but those limits cannot be confused with a contractual limitation of the professional's liability towards their client. The professional may be liable to the client beyond the limits of their insurance, and the existence of a policy does not legitimise contractual clauses reducing liability to the sum insured or to the fees.
6.Conclusion: freedom of contract yes, but not in order to hollow out liability
STS 949/2026 marks a milestone in defining how far a professional may go in contractually limiting their own liability. Freedom of contract allows reasonable limits to be agreed, particularly in contracting between professionals, but it does not protect clauses which, by their configuration, distort the compensatory function of contractual liability, allow the debtor to self‑determine their liability ceiling through their fees and operate with indifference to the seriousness of the breach.
Although the case concerns lawyers, the doctrine applies to auditors, tax advisers, engineers, consultants and other providers of professional services. Exclusion and limitation of liability clauses will need to be reviewed in the light of this judgment, weighing the proportionality of the limit, its relationship to the potential loss and its compatibility with good faith and with the minimum balance between the parties' obligations. Professional liability cannot become a mere residual cost set unilaterally by the provider; it remains an essential element of confidence in professional services and an indispensable instrument for the protection of clients and the correction of breaches.
