Peer-to-Peer Loans in Spain: How to Do It Legally

🇪🇸 Read the original in Spanish

Lending money to a family member or a friend is an extremely common practice in Spain to fund personal projects, buy a home, or get through a financial rough patch. However, mutual trust should never be an excuse to bypass the law. A poorly structured loan can trigger serious problems with the Spanish Tax Agency, the Agencia Tributaria (commonly known as Hacienda), or lead to difficult family conflicts. In this article, we explain in detail, clearly and under the Spanish legal framework, how to carry out a peer-to-peer loan in a way that is 100% legal, secure, and free from tax penalties.

The Legal Framework of Peer-to-Peer Loans: What Does the Civil Code Say?

The loan agreement between individuals is fully recognized and regulated under the Spanish legal system. The governing legislation is the _Código Civil_ (Civil Code), which distinguishes between two types of loans in its Article 1740: comodato (if something non-fungible is lent for use and returned) and simple préstamo or mutuo (simple loan), which is the one that concerns us when dealing with money or other fungible goods.

Article 1753 of the _Código Civil_ establishes that whoever receives a loan of money or another fungible thing acquires ownership of it, and is obliged to return to the creditor an equal amount of the same kind and quality.

One of the most frequent questions is whether these types of transactions must obligatorily accrue interest. The answer is no. Article 1755 of the _Código Civil_ expressly determines that no interest shall be due unless it has been expressly agreed upon. Therefore, in Spain, it is perfectly legal to make a loan at 0% interest (interest-free), as long as it is declared and formalized properly to prevent Hacienda from mistaking it for a hidden donation.

In the event of default and the need to file a legal claim, the _Ley de Enjuiciamiento Civil_ (Civil Procedure Act - Law 1/2000) provides the appropriate procedural channels (such as the proceso monitorio [payment order procedure] or the juicio ordinario/verbal [ordinary/verbal trial], depending on the amount) to demand the return of the funds, provided that documentary proof of the contract is available.

The Danger of a Hidden Donation and the Role of Hacienda

The main risk of not formalizing a loan in writing is that the Agencia Tributaria may presume it is a donation (a gift).

• The Loan is a transaction subject to but exempt from the Impuesto sobre Transmisiones Patrimoniales y Actos Jurídicos Documentados (ITP-AJD - Property Transfer and Documented Legal Acts Tax). This means that no taxes are paid for receiving or returning the money.
• The Donation is taxed under the Impuesto sobre Sucesiones y Donaciones (ISD - Inheritance and Gift Tax). Except in autonomous communities with very high tax reliefs, donations entail paying a significant percentage of the money received, in addition to potential penalties for not declaring it on time.

If Hacienda detects a significant transfer of money between the accounts of individuals without a contract to justify it, they will demand the payment of the Gift Tax plus the corresponding late-payment interest.

Practical Steps to Legalize the Loan

For the loan to be fully valid before third parties and the Tax Administration, you must strictly follow these 4 steps:

1. Draft and Sign a Written Loan Agreement

This is the fundamental document. It can be done through a documento privado (private document signed by the parties) or through an escritura pública (public deed) before a notario (notary). Although a private document is perfectly valid and free of charge, the contract must obligatorily contain the following details:

• Date and place of signing.
• Full identification details of the lender (the person lending the money) and the borrower (the person receiving it), including first name, surname, NIF/NIE, and address.
• The exact amount of the loan (the principal).
• The repayment term and payment schedule (monthly, quarterly, single payment at the end, etc.).
• The applied interest rate. If it is interest-free, it must be expressly stated: "The loan shall not accrue any interest (0% interest)".
• Clauses in case of default or early repayment.

2. Make a Bank Transfer (Avoid Cash)

Under no circumstances should the money be handed over in cash. The best proof of the transaction's existence is bank traceability. Make a transfer where the concept clearly states: "Loan from [Lender's Name] to [Borrower's Name]". Keep the bank receipt together with the contract.

3. Submit Form 600 (Modelo 600) to the Regional Tax Office

This is the step most people forget, and it is the most important one to avoid fines. Since it is a transaction subject to but exempt from the Impuesto sobre Transmisiones Patrimoniales (ITP), you must submit _Modelo 600_ (Form 600) to the tax office of your Autonomous Community.

• The submission deadline is 30 business days starting from the date the contract is signed.
• The result of the self-assessment will be 0 euros (exempt), so you will not have to pay anything, but the submission provides the contract with a fecha fehaciente (certified date) before the Administration.
• You must provide the original signed contract and a copy of it.

4. Repay the Loan Exclusively Through the Bank

As the repayment deadlines are met, the borrower must transfer the installments to the lender's account using clear concepts such as "Repayment of loan installment [Month/Year]". This will serve as proof in the event of any tax inspection trying to claim that the loan was simulated.

Key Deadlines, Amounts, and Figures You Must Know

To avoid violating the Ley de Prevención del Blanqueo de Capitales (Anti-Money Laundering Act) and to optimize the transaction tax-wise, keep these reference figures in Spain in mind:

• €10,000: This is the threshold of money that banking entities are obliged to report directly to the Bank of Spain and Hacienda for any incoming or outgoing account movement.
• €3,000: Although the mandatory reporting limit is €10,000, Hacienda monitors closely and can request clarifications for any transfer or cash deposit exceeding €3,000.
• 30 business days: This is the legal and non-extendable deadline to submit _Modelo 600_ after signing the loan contract.
• 0%: The minimum legal interest rate that can be applied if expressly agreed in the contract.
• 4 years: This is the general statute of limitations period that the Agencia Tributaria has to review and inspect tax returns corresponding to the transaction.

Concrete Examples of Practical Application

Below, we analyze two common scenarios to understand how these rules apply in daily life.

Example 1: Family Loan for the Purchase of a Vehicle

Carlos wants to buy a second-hand car that costs €12,000. Since he does not want to finance it through the dealership due to high interest rates, his mother, Sofía, decides to lend him the money at 0% interest to be repaid over 5 years (60 monthly installments of €200).

1. They draft a private contract detailing the conditions and specifying that the interest rate is 0%.
2. Sofía transfers €12,000 to Carlos's account with the concept "Family loan car Carlos".
3. Carlos submits _Modelo 600_ to his regional tax office within 30 days of signing, attaching the contract. He pays nothing for the tax (exempt).
4. Every month, Carlos transfers €200 to his mother's account. Both keep the receipts. The transaction is 100% legal, and Hacienda cannot claim anything.

Example 2: Loan Between Friends with Agreed Interest

Elena needs €5,000 to start a design business. Her friend Javier agrees to lend it to her, but they agree on an annual interest rate of 2% (below the legal interest rate of money) to be returned in a single payment after 2 years (a total of €5,200).

1. They sign the contract detailing the amount of €5,000, the term of 24 months, and the interest rate of 2%.
2. They submit _Modelo 600_ (exempt from ITP).
3. After 2 years, Elena transfers €5,200 to Javier.
4. Tax treatment of interest: Since there is interest, Javier (the lender) must declare that €200 profit on his income tax return (IRPF) as rendimiento del capital mobiliario (investment income). Elena, as this is a non-commercial loan between individuals, does not have to withhold anything, but Javier must pay tax on that return.

Mistakes You Must Avoid

Making mistakes when formalizing a loan can be very costly. Avoid falling into the following practices:

• Not registering the contract with the Tax Office (not submitting Modelo 600): Even if you have a signed paper, if you do not present it to the regional registry, Hacienda can argue that the document was backdated to justify an inspection, treating it as a hidden donation.
• Setting unrealistic repayment terms: If an 85-year-old father lends €150,000 to his son to be repaid over 40 years, Hacienda will challenge it immediately. The repayment term must be consistent with the life expectancy and economic capacity of the parties.
• Forgiving debts verbally: If the lender decides to forgive the remaining money to be repaid, this automatically becomes a donation. A debt forgiveness document must be drafted, and the corresponding Gift Tax must be settled for the forgiven amount.
• Returning the money in cash or "under the table": If the borrower returns the money in cash without leaving a bank trail, to a tax inspector it will look as though the lent money was never returned, which nullifies the nature of the loan and triggers the presumption of a donation.

Frequently Asked Questions (FAQ)

Can a peer-to-peer loan be made without interest?

Yes, it is completely legal. The Código Civil allows loans to be free of charge. However, so that Hacienda does not presumptively apply the legal interest rate of money, it is mandatory that the written contract explicitly states that the loan does not accrue interest (interest at 0%).

What happens if the borrower dies before repaying the money?

The death of the debtor does not extinguish the debt. The lender's right to collect is transferred to the deceased's heirs as part of the liabilities of the estate (debts are also inherited), in accordance with the Código Civil. The heirs must take charge of returning the remaining money.

And what if the person who dies is the lender?

In this case, the right to collect the remaining money becomes part of the lender's estate (the assets). The borrower must continue paying the installments to the lender's legitimate heirs. If the borrower is, in turn, an heir (for example, a child), the debt may be extinguished by confusión de derechos (merger of rights, where one becomes the debtor and creditor of oneself), integrating the outstanding balance into their share of the inheritance.

Is it mandatory to go to a notary to formalize the loan?

No, it is not mandatory. A private contract signed by the parties has full legal validity. However, going to a notario provides superior legal certainty (direct executive force in case of default under the Ley de Enjuiciamiento Civil) and gives the document an unquestionable public date, although it carries notary fee costs.

Can the repayment term of an already registered loan be extended?

Yes. To do this, an addendum to the original contract signed by both parties must be drafted, agreeing on the new term conditions. Subsequently, this addendum must be submitted along with _Modelo 600_ to the Tax Office, indicating that it is a novación (modification) or extension of the initial loan.

In Summary

• Legality: Peer-to-peer loans are fully legal in Spain and can be agreed at 0% interest if expressly stated in writing.
• Mandatory contract: A detailed contract must always be drafted, whether public (notary) or private, identifying the parties, the amount, the terms, and the interest rate.
• Key tax procedure: It is mandatory to submit _Modelo 600_ to the tax office of your Autonomous Community within a maximum period of 30 business days from signing the contract.
• Tax-exempt: The loan is an exempt transaction under ITP, so submitting Form 600 is free but indispensable to avoid fines from Hacienda.
• Banking traceability: All handovers and returns of money must be carried out via bank transfer to ensure traceability in the event of any tax inspection.

General legal information, not personalised legal advice. For your specific situation, ask your question for free at AbogadoAI — answers grounded in Spanish law (BOE), in English.

This is general information, not legal advice. Verify on the BOE or consult a lawyer for your specific case.