Family Loan Agreement Mexico

A Family Loan Agreement Mexico (Contrato de Préstamo Familiar) is a civil law contract formalising the transfer of money from one family member (prestamista) to another (prestatario) under the legal framework of the contrato de mutuo civil established by the Código Civil Federal (CCF) Articles 2384 through 2397. Unlike a commercial loan (mutuo mercantil) governed by the Código de Comercio, the family loan is a personal civil transaction between individuals related by blood (parentesco consanguíneo) or marriage (parentesco por afinidad), and does not require the intervention of a financial institution or notary unless real property is offered as collateral.

Article 2384 CCF defines the contrato de mutuo as a contract by which one party (mutuante or prestamista) transfers ownership of a fungible good — most commonly money — to another party (mutuatario or prestatario), with the obligation to return an equal quantity of the same type and quality at an agreed time. Article 2393 CCF establishes the general rule that the mutuo is interest-free (mutuo gratuito) unless the parties expressly agree to charge interest (intereses pactados) in writing — oral agreements on interest are not enforceable under Article 2394 CCF.

For tax purposes, the Servicio de Administración Tributaria (SAT) has issued administrative criteria and jurisprudencia establishing that intra-family loans that are not documented with a formal written contract, CFDI receipts, and consistent repayment flows may be reclassified as donaciones (gifts) under ISR Article 93 Section XIX, triggering income tax liability for the recipient on the amount received. The SAT has specifically scrutinised large transfers between family members as potential mechanisms for informal wealth transfers or tax evasion, issuing binding criteria in Miscelánea Fiscal annual resolutions requiring that intra-family loans above MXN 600,000 be documented with a formal written agreement, show consistent interest payments (if interest is charged), and have repayment flows that match the agreed schedule in the prestamista's and prestatario's bank accounts.

The contrato de mutuo civil between family members must be distinguished from the acto de liberalidad (act of liberality) or donación under CCF Articles 2332 through 2383. A donación is an irrevocable transfer of assets without obligation of repayment, subject to Impuesto Sobre la Renta (ISR) exemptions for close family members under LISR Article 93 Section XIX (up to three times the annual UMA value in 2025, approximately MXN 316,000), while the mutuo is a loan creating a genuine repayment obligation. Structuring a donation as a loan solely to avoid ISR without genuine repayment intention constitutes simulación fiscal under Código Fiscal de la Federación (CFF) Article 5-A and can result in fiscal differences (diferencias fiscales) being assessed by the SAT.

When real property is offered as collateral for a family loan, the guarantee must be formalised as an hipoteca (mortgage) under CCF Articles 2893 through 2941 and registered with the Registro Público de la Propiedad to be enforceable against third parties. Registration of the hipoteca triggers notarial fees (honorarios notariales) and Registro Público registration fees (derechos de registro) set by the applicable state tariff law. For family loans without real property collateral, a pagaré signed by the borrower provides the most effective enforcement mechanism through juicio ejecutivo mercantil under Código de Comercio Article 1391.

A Family Loan Agreement Mexico is needed whenever money is transferred between family members with a genuine expectation of repayment, and the parties wish to protect their respective interests and comply with SAT documentation requirements.

The agreement is required when parents lend money to adult children for a major purchase — real estate down payment, business investment, vehicle purchase, or education expenses — and the parents expect repayment. Without a written contract, the SAT may reclassify the transfer as a donation subject to ISR, the borrower may dispute the loan nature of the transfer, or the lender's estate may face complications regarding the outstanding balance at the time of the lender's death.

A Family Loan Agreement is needed when siblings (hermanos) provide financial support to each other during a business venture, personal crisis, or investment opportunity. The agreement documents the loan terms, repayment schedule, and any interest agreed, preventing misunderstandings that commonly damage family relationships when informal loans go unrepaid.

The contract is required when grandparents (abuelos) fund grandchildren's housing, education, or business startup — amounts that are significant enough to trigger SAT scrutiny of the family's financial transactions. The Resolución Miscelánea Fiscal requires taxpayers who receive cash transfers above MXN 600,000 in a calendar year to demonstrate the legal basis for the transfer; a formal Family Loan Agreement satisfying CCF Articles 2384 through 2397 is the primary documentary evidence for this purpose.

The agreement is also needed in estate planning (planeación sucesoria) contexts where parents wish to advance inheritance to children through loans rather than donations — the loan structure allows the parents to recover the capital if circumstances change, while a formal donación under CCF Article 2332 is irrevocable. A Notario Público or abogado civilista should advise on whether the specific family financial arrangement is better structured as a mutuo, a donación, or an anticipo de herencia (advance on inheritance) for both civil and tax purposes.

The document is required when in-laws (suegros) or extended family members (familiares en línea colateral) provide financial assistance for housing — particularly common in Mexico when family networks collectively fund the purchase of residential property. In such cases, the written mutuo under CCF Articles 2384 through 2397, supported by SPEI transfer records and annual ISR declaration disclosures, protects both the lending family member's patrimonial interest and the borrowing family member's credit history with the Buró de Crédito if the loan is later formalised through a financial institution.

A Family Loan Agreement Mexico under CCF Articles 2384 through 2397 must include the following elements to be legally enforceable and SAT-compliant:

Identification of Parties and Family Relationship: Full legal name, CURP (Clave Única de Registro de Población), RFC, and address of both the prestamista (lender) and prestatario (borrower), plus a statement of the family relationship between them (e.g., madre e hijo, hermanos, cónyuge). The family relationship is relevant for SAT ISR exemption analysis under LISR Article 93 and for determining applicable CCF rules on family patrimony.

Loan Amount and Delivery Method: The exact amount of the loan (monto del préstamo) in MXN, the date on which funds were or will be transferred, and the delivery method — bank transfer (transferencia bancaria SPEI), cash (efectivo), or cheque. For SAT compliance, bank transfer is strongly preferred as it creates a documented money trail (rastreabilidad de fondos). The agreement should reference the bank account details and, where possible, attach the SPEI transfer confirmation.

Repayment Terms: The total repayment period (plazo total), repayment schedule (calendario de pagos) — monthly, quarterly, or in a single balloon payment (pago único al vencimiento) — each installment amount, and the final repayment date. The repayment schedule should be realistic and consistent with the borrower's income level, as the SAT may question a repayment schedule that is inconsistent with the borrower's declared income under LISR.

Interest Provisions: An express statement of whether the loan bears interest (préstamo con intereses) or is interest-free (préstamo sin intereses, mutuo gratuito). Under CCF Article 2393, the mutuo civil is presumed to be interest-free unless interest is expressly agreed in writing. If interest is charged, the agreed rate (tasa de interés pactada) must be stated and must not exceed the applicable legal interest rate — courts may reduce usurious rates under SCJN jurisprudencia on usura. For tax purposes, interest received by the prestamista is ingreso por intereses subject to ISR under LISR Article 133, with 20% provisional ISR withholding applicable.

Guarantee and Security: If the borrower offers a guarantee (garantía) — a pagaré signed by the borrower, a third-party guarantor (fiador), a pledge of personal property (prenda), or a real property mortgage (hipoteca) — this must be documented separately or as an annex to the agreement. A pagaré is the most practical security for family loans as it allows enforcement through juicio ejecutivo mercantil without requiring notarial intervention for the loan agreement itself.

Default and Remedies: A definition of default (incumplimiento) — typically failure to make three consecutive installment payments — and the lender's remedies upon default, including acceleration of the entire outstanding balance (vencimiento anticipado), charging of default interest (intereses moratorios), and enforcement of any guarantee provided. Default interest should comply with SCJN usura jurisprudencia.

SAT Compliance Annex: For loans above MXN 600,000, the agreement should reference the parties' obligations to reflect the loan in their annual ISR declarations — the prestamista as a creditor asset (activo patrimonial), the prestatario as a liability (pasivo patrimonial) — to ensure the transaction is consistent with declared patrimony under SAT anti-tax-evasion rules.

Governing Law: An express statement that the Family Loan Agreement Mexico is governed by the Código Civil Federal and, for any disputes not resolved between the parties, that ordinary civil jurisdiction before the Juzgado Civil competente in the parties' domicile applies. For amounts below MXN 500,000, the Juzgado de Paz Civil or Juzgado de Cuantía Menor may have jurisdiction, reducing litigation costs. Forms-legal.com provides this template as a practical starting point — consulting a Contador Público Autorizado (CPA) and a Licenciado en Derecho ensures the loan structure is both civil-law sound and SAT-compliant.