The claim changes creditor, but does the obligation change? Assignment of claims, ancillary rights and the debtor's defences
The assignment of claims is a central institution of the law of obligations and of contractual practice. It allows a creditor to transfer his claim to a third party, with its security and ancillary rights, without the need to create a new obligation. The “Código Civil” —the Spanish Civil Code, CC—, from articles 1526 onwards, and the “Ley Hipotecaria”, Spain's Mortgage Act, in its provisions on the assignment of mortgage-secured claims, provide the basic framework for analysing what is transferred with the claim, what part is played by the debtor's consent and by notice to him, what effects payment to the assignor has, what defences the debtor may raise against the assignee and how set-off operates. STS 22/2026 of 14 January, a judgment of the “Tribunal Supremo”, Spain's Supreme Court, returns to an essential principle: assignment does not create a new obligation, the assignee acquires the same claim, with its identity and content, and the change of creditor is not equivalent to the birth of a different claim. That principle makes it possible to build a broad body of doctrine on the identity of the obligation, the debtor's position and the difference between assignment, subrogation and novation.
1.The concept of assignment of claims and the transfer of ancillary rights
The “Código Civil” —the Spanish Civil Code, CC— provides that the assignment of a claim, right or action shall not take effect against a third party save from such time as its date is to be treated as certain, in accordance with the rules on private documents, and that, where it relates to immovable property, from the date of its registration in the Registry. Assignment is a transaction between assignor and assignee by which the former transfers to the latter his position as creditor vis-à-vis the debtor, without any need to alter the underlying obligation. The sale or assignment of a claim includes that of all ancillary rights, such as suretyship, mortgage, pledge or preferential right. This means that the assignee acquires not only the principal claim but also the security in rem and the personal security accompanying it, to the extent that these are transferable and are not tied intuitu personae to the assignor.
In the mortgage field, the “Ley Hipotecaria”, Spain's Mortgage Act, provides that a claim or loan secured by a mortgage may be assigned in whole or in part in accordance with the Civil Code, and that the assignment of title to the mortgage must be made by public deed and registered at the “Registro de la Propiedad”, the Land Registry. The debtor is not bound by that contract to any greater extent than he was by his own, and the assignee is subrogated to all the assignor's rights. Where the mortgage has been created to secure obligations transferable by endorsement or bearer instruments, the mortgage right is deemed to be transferred together with the obligation or with the instrument, without any need to give notice to the debtor or to record the transfer in the Registry. Assignment therefore operates as a subrogation to the position of creditor, with the transfer of ancillary rights, but without any alteration of the content of the obligation.
2.Consent and notice to the debtor, discharging payment and effects against third parties
The assignment of a claim does not require the debtor's consent in order to be valid as between assignor and assignee. The debtor is a third party in relation to the assignment transaction, which is entered into between creditor and assignee. Notice to the debtor is, however, of practical and legal significance. The Civil Code provides that a debtor who pays the creditor before becoming aware of the assignment is released from the obligation. This means that, so long as the debtor has no notice of the assignment, he may validly pay the assignor and obtain his release, even though the claim has been transferred. The protection of the debtor is built around actual knowledge of the assignment, not around his consent.
The requirement of a certain date for an assignment to take effect against third parties, and that of registration where it relates to immovable property, reflect the need for legal certainty in the circulation of claims and in the protection of third-party purchasers or creditors. An unregistered assignment of a mortgage-secured claim may be valid as between assignor and assignee, but it cannot be set up against third parties who rely on the registered title. The Mortgage Act adds that, where in the cases in which it is required notice of the assignment of the mortgage-secured claim is not given to the debtor, the assignor will be liable for any loss the assignee may suffer as a consequence of that omission. Failure to give notice does not invalidate the assignment, but it shifts to the assignor liability for any prejudicial effects it may have for the assignee, for example, a discharging payment made to the assignor.
3.The identity of the obligation: assignment does not create a new claim
STS 22/2026 of 14 January, in an insolvency context, reaffirms that the assignment of a claim does not entail the birth of a new obligation but a mere subrogation to the creditor's position. The obligation transferred remains identical in its entirety and content. The assignee acquires the claim with the same nature and classification as it had in the assignor's hands. In that case, the issue was whether a claim acquired by assignment before the declaration of insolvency was to be classified as subordinated on the ground that the assignee was a person specially related to the debtor. The insolvency practitioners argued that the relevant moment for assessing the special relationship was that of the acquisition of the claim by the new creditor, whereas the Supreme Court holds that the element of blameworthiness justifying subordination must be present at the moment when the claim arose, not at the moment of its transfer.
The Chamber recalls its settled case law and lays down that, in order to determine whether a claim is subordinated by reason of the existence of a special relationship, the decisive moment is that at which the claim arose. Assignment does not alter the nature of the obligation or its classification; the assignee takes the same position as the assignor. That doctrine is of general scope: a change of creditor does not turn the claim into a different one, nor does it allow its essential features to be reconfigured. The identity of the obligation is a precondition of legal certainty in the circulation of claims and of the protection of the debtor, who cannot be subjected to a more onerous regime merely because his creditor changes.
4.Defences available to the debtor against the assignee: set-off and other defences
The assignment of a claim raises the question of which defences the debtor may raise against the new creditor. The general regime, in the absence of agreement or of a special rule, is that the debtor may raise against the assignee the same defences as he had against the assignor, to the extent that they are intrinsic to the claim transferred. Academic commentary distinguishes between intrinsic defences, which go to the existence, validity, enforceability or amount of the claim, and extrinsic defences, which relate to personal dealings between debtor and assignor unconnected with the claim. The former, such as nullity of the contract, limitation, part payment, the fact that the claim has not fallen due or set-off against claims arising from the same relationship, may be raised against the assignee. The latter, such as the debtor's personal claims against the assignor unconnected with the claim transferred, may be restricted by the assignment.
The Civil Code specifically governs set-off in the case of assignment. It provides that a debtor who has consented to an assignment of rights made by a creditor in favour of a third party may not raise against the assignee the set-off that would have been available to him against the assignor. If the creditor gave him notice of the assignment and the debtor did not consent to it, he may raise set-off in respect of the debts predating it, but not of those arising afterwards. If the assignment is made without the debtor's knowledge, he may raise set-off in respect of the claims predating it and of those arising afterwards until he became aware of the assignment. That regime distinguishes three situations according to the debtor's consent and knowledge, and limits set-off in time in order to protect the assignee against set-off in respect of claims arising after the assignment where the debtor has consented or has been given notice.
Set-off further requires that both persons be reciprocally creditor and debtor in their own right, that the debts consist of a sum of money or of fungible goods of the same kind and quality, that they be due, liquidated and payable, and that none of them be subject to any retention or dispute raised by third parties and duly notified to the debtor. Set-off is not available where one of the debts arises from a deposit or from the obligations of a depositary or borrower for use, nor may it be raised against a creditor in respect of maintenance owed under a gratuitous title. A surety may nevertheless raise set-off in respect of what the creditor owes to his principal debtor. Debts payable in different places may be set off subject to indemnification of the costs of transport or of exchange to the place of payment. This web of requirements and exceptions bears on assignment: the debtor retains the possibility of set-off on the terms of article 1198, but its scope is modulated by his consent to or knowledge of the assignment.
Beyond set-off, academic commentary has debated what becomes of other defences when the debtor consents to the assignment. One restrictive position takes the view that the debtor's consent entails a waiver of extrinsic defences, but not of those intrinsic to the claim, save where he specifically declares otherwise. Another position, more protective of the debtor, maintains that not even consent should be construed as a tacit waiver of material defences, particularly in consumer settings or in standard-form contracting. In any event, assignment cannot deprive the debtor of defences going to the existence or validity of the claim, such as nullity of the contract, unlawfulness of the cause or absence of consent.
5.Assignment, subrogation and novation: structural differences
The assignment of a claim must be distinguished from subrogation and from novation. The Civil Code contemplates the modification of obligations by varying their object or their principal conditions, by substituting the person of the debtor or by subrogating a third party to the creditor's rights. Objective novation, which consists in substituting one obligation for another, requires that it be declared in unequivocal terms or that the old and the new obligation be wholly incompatible. Subjective novation, which consists in substituting a new debtor for the original one, may be effected without the latter's knowledge, but not without the creditor's consent. The insolvency of the new debtor accepted by the creditor does not revive the action against the original debtor, unless that insolvency was prior and public or known to the debtor when he delegated his debt.
The subrogation of a third party to the creditor's rights may occur by operation of law or by the will of the parties. The Civil Code warns that subrogation is not to be presumed outside the cases expressly mentioned and that, in all others, it must be clearly established in order to take effect. Subrogation by payment by a third party, governed by the articles on payment, allows a person who pays on another's account to be subrogated to the creditor's rights, to the extent so agreed or so provided by law. Academic commentary has stressed that, where subrogation operates by agreement between creditor and solvens, the content of that agreement determines the measure and the degree of intensity of the subrogation, so that the security, the defences and the debtor's position may be modulated.
Assignment, by contrast, is a transaction transferring the claim which neither alters the obligation nor requires payment. The assignee acquires the claim as it stands, with its ancillary rights and with the defences the debtor may raise. Novation does create a new obligation, extinguishing the previous one, and may substantially alter the content of the relationship, whereas subrogation by payment stands at an intermediate point, since it entails the extinction of the obligation owed to the original creditor and the creation of a new relationship between debtor and solvens, albeit with a content similar to that of the claim paid. STS 22/2026 stresses that assignment is not novation and that it cannot be used to reconfigure the nature of the claim or its classification, particularly in insolvency settings.
6.The assignor's liability and the assignee's risks
The Civil Code also governs the assignor's liability towards the assignee. A seller acting in good faith is answerable for the existence and legitimacy of the claim at the time of the sale, unless it has been sold as doubtful, but not for the debtor's solvency, unless this has been expressly stipulated or the insolvency was prior and public. Even in those cases, he is answerable only for the price received and for the expenses determined by law. A seller acting in bad faith is always answerable for the payment of all expenses and for damages. Where an assignor acting in good faith has made himself answerable for the debtor's solvency and nothing has been stipulated as to the duration of that liability, it lasts one year from the assignment if the claim had already fallen due, one year from maturity if the claim was payable at a term that had not yet fallen due, and ten years from the assignment if the claim consists of a perpetual annuity.
Where a litigious claim (“crédito litigioso”) is sold, the debtor is entitled to extinguish it by reimbursing the assignee the price he paid, the costs incurred by him and the interest on the price from the day on which it was paid. A claim is regarded as litigious from the moment a defence is filed to the claim relating to it, and the debtor may exercise his right within nine days from the assignee's demand for payment. Excepted from this regime are assignments made to a co-heir or co-owner of the right assigned, to a creditor in payment of his own claim and to the possessor of a property subject to the litigious right being assigned. These rules show that the assignment of claims is not neutral in terms of risk: the assignee assumes the risk of the debtor's insolvency, unless otherwise agreed, and may be exposed to the debtor's power to extinguish the litigious claim on specific conditions.
7.Conclusion: change of creditor, identity of the obligation and the debtor's defences
The assignment of claims allows rights of credit to circulate without altering the underlying obligation. The claim changes creditor, but the obligation does not change: the assignee acquires the same claim, with its identity and content, with its security and ancillary rights, and takes the assignor's position vis-à-vis the debtor. The debtor need not consent to the assignment, but his knowledge of it matters for the effectiveness of a discharging payment and for the delimitation of set-off. Assignment cannot deprive him of defences intrinsic to the claim, such as nullity, limitation, payment or the fact that it has not fallen due, and it limits set-off only on the terms of article 1198, according to his consent or knowledge.
STS 22/2026 reinforces the idea that assignment does not create a new obligation and that the relevant moment for classifying the claim is that at which it arose, not that at which it was transferred. The difference between assignment, subrogation and novation is essential for litigation practice and for the structuring of financing, refinancing and claims portfolio transfer transactions. For contractual practice, the assignment of claims in business, in banking, in sales finance and in portfolio management requires it to be borne in mind that a change of creditor cannot aggravate the debtor's position or alter the nature of the claim, and that the debtor's defences, properly understood, are a structural element of legal certainty in the circulation of claims.
