Cross-Border Unjust Enrichment in Turkey: MÖHUK Article 39, Underlying Relationship and Place of Enrichment

1. Article 39 links restitution to the legal reason for the transfer

Unjust enrichment is a restitutionary claim. It asks whether one person received or retained an economic benefit without a legally valid basis at the expense of another. In an international dispute, the first task is not simply to ask where the claimant or recipient lives. The court must identify the legal event that produced the enrichment.

Article 39 uses that event as the main connecting factor. Where a contract, debt, mandate, property transaction or other legal relationship explains why the value moved, the law governing that relationship also governs the restitution claim arising when the basis fails.

This approach prevents a party from escaping the contract’s governing law merely by relabelling the same dispute as unjust enrichment.

2. An existing legal relationship controls when it caused the enrichment

Suppose a German buyer pays a Turkish supplier under a sale contract governed by German law, but the contract is later rescinded and repayment is sought on an unjust-enrichment basis. Article 39 first points back to the law governing the sale relationship because that relationship caused the payment.

The same principle can apply to agency, loan, employment, construction, licence and service relationships. The law governing the relationship supplies the restitution rules when performance loses its legal basis.

The claimant should therefore identify the original legal relationship and its governing law before pleading a standalone enrichment theory.

3. Even an alleged legal relationship can determine the governing law

Article 39 expressly refers not only to an existing relationship but also to one alleged to exist. This matters when one party says there was a contract and the other denies that any contract was concluded.

If the enrichment occurred because the parties acted on the assumption of that disputed relationship, the conflict rule can still follow the law that would govern the alleged relationship.

This avoids circular reasoning in which the court would need to prove the contract exists before it can determine the law governing the restitution consequences of a contract said not to exist.

4. Invalid contracts frequently lead to Article 39 restitution

A contract can be invalid because of form, incapacity, illegality, lack of authority or another substantive defect. Money or property may nevertheless have changed hands before invalidity is established.

The law governing the contract’s existence and material validity under MÖHUK Article 32 can therefore become the Article 39 governing law for restitution.

For Turkish real-estate sales, mandatory form rules are especially important. A private foreign agreement cannot replace a Turkish title-deed transfer where the law requires official form, and payments made under an invalid structure can produce restitution claims.

5. Performance that loses its legal basis can create a repayment claim

A payment may have a valid basis when made but lose that basis later. A contract can be terminated, a condition can fail, an administrative approval may not be obtained, or a transaction can be rescinded.

The governing substantive law determines whether the recipient must return the benefit, whether deductions are allowed and what happens to benefits consumed or transformed.

The date the legal basis disappeared can also matter for interest and limitation calculations.

6. Wrong international bank transfers often have no underlying relationship

When a person accidentally transfers money to the wrong Turkish IBAN and has no contract or debt relationship with the recipient, Article 39’s second route becomes central. The claim is governed by the law of the country where the enrichment occurred.

Determining that country requires more than identifying the sender’s bank. The recipient’s account, receipt of funds and economic benefit must be analysed.

Our existing wrong Turkish IBAN recovery guide explains the practical evidence and recovery process, while this page addresses the conflict-of-laws question.

7. Duplicate payments can arise from contract or pure mistake

If an invoice is paid twice under a valid contract, the contract itself explains the transfer and the governing law of that contract can follow the restitution claim. If the second payment went to an unrelated recipient due to a banking error, the enrichment-place rule can instead be relevant.

The claimant should trace each transfer separately and identify whether the recipient had any underlying right to receive it.

Bank records, invoice numbers, payment references and reconciliation statements are important evidence.

8. Failed property transactions require separation of property law and restitution law

A foreign buyer can transfer a deposit or purchase price for Turkish real estate but fail to acquire title because the official transaction is never completed. Turkish property law governs the property/form issues under Article 25, while Article 39 addresses repayment of benefits transferred without a surviving basis.

If the failed contract itself is governed by Turkish law, Article 39 generally follows that legal relationship. The buyer should not assume a foreign payment source changes the governing law.

Claims against an agent who retained money can also involve mandate, tort or fiduciary theories that require separate classification.

9. Money between relatives can be loan, gift or unjust enrichment

Cross-border family transfers often produce disputes because the bank record shows money moved but not why. One party says it was a loan, another says it was a gift, while a third argues it was sent for a property purchase that never occurred.

Article 39 cannot be applied correctly until the alleged legal basis is identified. If a loan is alleged, the law governing that loan relationship becomes relevant even if the court later concludes no enforceable loan existed.

Messages, transfer descriptions, subsequent acknowledgments and the parties’ conduct can help classify the transaction.

10. When no relationship exists, identify where the enrichment actually occurred

The statute uses the country where the enrichment took place. This is not necessarily the country where the claimant became poorer. The focus is on where the recipient obtained the economic benefit.

For physical property, location of receipt can be clear. For bank transfers and digital assets, the account structure and recipient’s economic control require analysis.

The court should avoid applying the claimant’s home law merely because the loss was felt there.

11. Bank-account location is important but not always the entire analysis

A transfer credited to a Turkish bank account strongly connects enrichment to Türkiye, but complex correspondent banking, escrow or payment-platform structures can require deeper examination.

The legally enriched person should also be identified. A company account controlled by a company is not automatically enrichment of the shareholder personally.

Recipient identity and account ownership should be obtained through lawful banking evidence rather than assumptions based on an IBAN name.

12. Parties may choose law only after the enrichment has occurred

Article 39(2) permits an express choice of law after the enrichment. The timing is important. A general clause written before the event cannot automatically function as an Article 39(2) choice unless it is part of the underlying relationship whose law already controls under Article 39(1).

After a dispute arises, parties can expressly agree on a law for restitution, for example in a settlement protocol.

The choice should be written clearly to avoid later disagreement over its scope.

13. The governing law determines how much must be returned

Unjust-enrichment law can distinguish the original benefit, substitute value, profits, expenses and benefits no longer retained. The governing law determines the scope of restitution and available defences.

A claimant should not assume the full transferred amount is always recoverable without deductions. A recipient may raise legally recognised expenses or change-of-position arguments depending on the governing law.

Interest start dates can also differ.

14. Good faith does not necessarily eliminate restitution

A recipient may honestly believe a payment was due. Good faith can affect the extent of liability under the governing substantive law, particularly if the benefit was consumed before the recipient learned of the lack of legal basis.

Once the recipient receives a clear repayment demand and learns of the mistake, later disposal of the funds can be treated differently.

Written notice therefore has evidentiary importance beyond simply requesting payment.

15. Limitation should be calculated under the correct governing law

Unjust-enrichment claims can have discovery-based and absolute limitation periods. Which period applies depends on the substantive law selected under Article 39.

Do not calculate Turkish limitation automatically because the lawsuit will be filed in Türkiye. A foreign governing law can contain materially different deadlines.

The claimant should preserve dates of payment, discovery, demand and any acknowledgment.

16. Governing law does not answer which court can hear the claim

International jurisdiction remains a separate MÖHUK Article 40 issue. A Turkish court can potentially hear a restitution claim governed by foreign law, and a foreign court can apply Turkish law under its own conflict rules.

For money in a Turkish account, defendant domicile, place of performance and enforcement assets can all influence litigation strategy.

Service abroad and collectability should be analysed before filing.

17. Build the claim around the transfer chronology

Essential evidence commonly includes bank statements, SWIFT records, contracts or draft contracts, invoices, messages explaining the transfer, account ownership evidence, repayment demands and any response from the recipient.

If the claimant alleges that no contract existed, preserve the communications showing the limited purpose for which the money was sent.

Foreign-language records should be translated consistently and original electronic files retained where possible.

Conclusion

MÖHUK Article 39 connects unjust enrichment to its legal source. If an existing or alleged legal relationship caused the enrichment, the law governing that relationship controls the restitution claim. If there is no underlying relationship, the law of the country where the enrichment occurred applies. The parties can expressly choose law only after enrichment has taken place. For wrong transfers, failed contracts and cross-border payments, accurate classification of the transaction is more important than the nationality of the parties.