Real Property Acquisition Tax (ISAI) Declaration Mexico (Declaración del Impuesto sobre Adquisición de Inmuebles)

The Real Property Acquisition Tax (ISAI) Declaration Mexico (Declaración del Impuesto sobre Adquisición de Inmuebles — ISAI, also called Impuesto sobre Traslación de Dominio in some states) is the state-level tax instrument filed by the acquirer of real property (inmueble) with the applicable state tax authority — the Tesorería del Estado, the Secretaría de Finanzas, or the Secretaría de Administración Tributaria Estatal — as a mandatory condition for the notarization and registration of any real estate transfer in Mexico. ISAI is a state tax (impuesto estatal) established in each state's Código Fiscal del Estado or Ley de Hacienda del Estado, which means that applicable rates, exemptions, calculation methods, and filing procedures vary by jurisdiction across Mexico's 31 states and the Ciudad de México.

The constitutional and legal foundation for state property acquisition taxes derives from the fiscal federalism framework under the Constitución Política de los Estados Unidos Mexicanos Article 31 Fraction IV (duty to contribute to public expenses) and the Ley de Coordinación Fiscal, which distributes taxing powers between the federal government and states. Real property acquisition — one of the traditional state tax bases under Mexican fiscal federalism — was not surrendered to federal coordination as part of the major tax base-sharing arrangements, preserving each state's independent authority to tax real estate transfers within its territory.

In practice, ISAI is one of the most significant transaction costs in any Mexican real estate purchase. Rates range from approximately 2% to 4.5% of the property's fiscal value or transaction price (whichever is higher) depending on the state — Ciudad de México imposes a rate of approximately 3%, Estado de México approximately 3.5%, Jalisco approximately 2%, and Nuevo León approximately 3%, with variations for residential versus commercial properties and for first-time homebuyer programs (programas de primera vivienda) that offer reduced rates for primary residence acquisitions below value thresholds.

The ISAI calculation base (base gravable) is typically the higher of: the transaction price stated in the notarial deed (precio pactado en escritura), the cadastral value (valor catastral) of the property as established by the municipal treasury (Tesorería Municipal) in the most recent property tax assessment, or the commercial value (valor comercial) determined by an appraisal (avalúo) certified by a Perito Valuador registered with the state or federal valuation registry. The Notario Público who authenticates the transfer deed is legally responsible for calculating, withholding, and remitting the ISAI to the state tax authority before the deed is presented for registration at the Registro Público de la Propiedad — making the notario the de facto ISAI collection agent in almost all residential and commercial real estate transactions.

The Registro Público de la Propiedad (RPP) — Mexico's real property public registry — will not register a transfer deed (escritura de traslación de dominio) without proof of ISAI payment. This makes ISAI payment a gateway condition (condición de inscripción) for the purchaser to obtain full legal title protection and priority against subsequent creditors and purchasers under the public registration principle (principio de publicidad registral) established in each state's Código Civil and Ley del Registro Público de la Propiedad.

The ISAI Declaration Mexico is required upon the completion of any taxable real estate acquisition in Mexico, encompassing virtually every form of transfer of property rights (derechos reales) in real estate from one person to another.

The declaration is needed for all purchase-sale transactions (compraventas): residential homes (casas habitación), apartments (departamentos), condominiums (condominios), commercial premises (locales comerciales), warehouses (bodegas), industrial facilities (naves industriales), and land (terrenos). The obligation falls on the buyer (adquirente), since ISAI is a tax on the acquisition of property — not on its sale.

ISAI is required for gratuitous transfers: real property received as a gift (donación), whether from a relative or a third party, is subject to ISAI at the same rates as a purchase, with the tax base calculated on the property's appraisal value since there is no stated purchase price. Most state Códigos Fiscales provide partial or full ISAI exemptions for direct-line family transfers (parents to children or between spouses) as part of social welfare policy.

The declaration is needed for property acquired through inheritance (herencia o legado) after the intestate or testate succession process concludes with adjudication of the estate — in most states, inheritance by direct heirs in the first degree (hijos, cónyuge) is exempt from ISAI, while inheritance by more distant relatives or unrelated persons is subject to ISAI at standard rates.

ISAI is required for transfers arising from partition of co-ownership (extinción del condominio or división de copropiedad), mergers of adjacent properties (fusión de predios), corporate restructurings involving real property transfers between legal entities, and transfers of real property held in fideicomisos (trust structures) when the beneficiary changes.

The declaration is also required for lease-to-own transactions (arrendamiento con opción a compra or arrendamiento financiero) when the option is exercised and the property is formally transferred, even though the economic transaction may have begun years earlier during the lease period.

Judicial auction acquisitions (adquisiciones en remate judicial) — where a property is purchased through a foreclosure proceeding (juicio hipotecario) or execution of a civil or commercial judgment — also trigger ISAI. The winning bidder in a remate judicial must pay ISAI to the state treasury before the court can issue the deed of adjudication (escritura de adjudicación judicial) that formalises the transfer. Courts typically require the ISAI payment receipt as a condition of issuing the adjudication order. The acquisition price in a remate is typically the winning bid amount, but the Notario or court may apply the three-value test if the bid falls below the cadastral or appraised value.

A complete ISAI Declaration Mexico under the applicable state Código Fiscal or Ley de Hacienda del Estado must include the following core elements, which are common across state jurisdictions despite state-specific variations in form format and calculation methodology.

Property Identification: Full cadastral description of the property being transferred — the official property account number (cuenta predial or clave catastral) assigned by the Tesorería Municipal, the property's full legal description (description as it appears in the Registro Público de la Propiedad: colonia, delegación or municipio, superficie total, construcción if any, límites y colindancias), and the current registration folio (folio real) or entry in the RPP. The cadastral key is essential because the municipal cadastral value (valor catastral) forms one of the potential bases for ISAI calculation.

Party Identification: Full legal name, RFC, CURP, and official identity document of the acquirer (adquirente). For corporate acquirers (personas morales), the RFC, constitutive act, and name and credentials of the legal representative are required. The seller's (enajenante's) full name, RFC, and identity are also typically included for cross-referencing purposes.

Transaction Details: Date of the purchase-sale or other acquisition contract (fecha del instrumento notarial), notarial instrument number (número de instrumento), name and notarial number of the authenticating Notario Público, and the agreed transaction price (precio pactado) as stated in the instrument.

Valuation for Tax Base: The three potential tax base values — transaction price (precio pactado), cadastral value (valor catastral from the most recent predial assessment), and commercial appraisal value (valor de avalúo) — must be stated, and the highest of the three is used as the ISAI tax base. The avalúo must be prepared by a Perito Valuador registered with the Sociedad Hipotecaria Federal (SHF), the Comisión Nacional Bancaria y de Valores (CNBV), or the state's authorized valuers registry, depending on the state's requirements.

ISAI Rate and Calculated Tax: The applicable ISAI rate from the state's Código Fiscal or Ley de Hacienda, and the computed ISAI amount. States with progressive ISAI rates — where higher-value properties face higher marginal rates — require showing the full bracket calculation. First-time homebuyer exemption or reduction (if applicable) must be supported by documentation proving the property will be the acquirer's primary residence (domicilio particular) and that the acquirer does not own other real property.

Payment and Receipt: ISAI is paid to the state treasury through the Notario or directly at state tax service windows (ventanillas de pago de Finanzas Estatales) before the deed is submitted for RPP registration. The payment receipt (comprobante de pago del ISAI) with the state treasury's official seal and folio number is attached to the notarial deed and presented to the RPP as proof of tax clearance (constancia de pago de impuestos).

Forms-legal.com provides this ISAI Declaration Mexico template as a reference guide for property buyers and their legal advisors. Because ISAI rates, exemptions, calculation methods, and payment procedures differ materially by state — and because the Notario Público assumes legal responsibility for correct ISAI calculation and remittance in notarized transactions — buyers should review ISAI obligations with their chosen Notario and, for high-value transactions, with a fiscal advisor (asesor fiscal inmobiliario) familiar with the specific state's current Código Fiscal and any applicable administrative rules or fee schedules issued by the state Secretaría de Finanzas. Annual updates to ISAI exemption thresholds, UMA multipliers, and primera vivienda program conditions are published in each state's Periódico Oficial and should be verified before closing. Under Article 31 Fraction IV of the Constitución Política, all residents of Mexico are obligated to contribute to public expenses — ISAI fulfils this constitutional mandate at the state level. Article 115 of the Constitution grants municipalities authority over the cadastral system used in ISAI valuations, and Article 27 governs the property rights framework underlying every real estate acquisition subject to ISAI.