Purchase Agreement vs. Final Deed in Mexico: Key Differences

When you buy or sell property in Mexico, you will often hear the terms "boleto de compraventa" (preliminary purchase agreement) and "contrato definitivo" (final contract) used as if they were synonyms, but they are not. Understanding the difference between a private purchase agreement and the public deed (escritura pública) can save you from significant financial losses and legal disputes that drag on for years. In this article we explain what each document is, what real protection it offers, and at what point in the purchase process each one should be signed.

What is a boleto or private purchase agreement

The boleto de compraventa, also called a private purchase agreement, is an agreement between buyer and seller that is signed before the deed is executed before a notary. In this document, both parties commit to completing the transaction under certain conditions: the agreed price, payment method, deadlines, delivery of the property, and penalties in case of breach.

This contract is normally signed on plain paper, without the involvement of a notary public, although it can be ratified before a notary to give it greater formality. Its main purpose is to lock in the terms of the transaction while the documentation needed for the final deed is gathered, a mortgage loan is processed, or an outstanding lien on the property is cleared.

It is common for a down payment or deposit (anticipo or apartado) to be handed over along with the private contract as a sign of commitment. This amount should be clearly described in the document, including what happens to it if the transaction falls through due to causes attributable to either party.

What is the final contract (public deed)

The final contract is the public deed (escritura pública) signed before a notary public which, once registered in the corresponding Registro Público de la Propiedad (Public Property Registry), formally transfers ownership of the property to the buyer. It is the only document that provides full legal certainty over title to the property as against third parties.

Unlike the private agreement, the public deed requires the notary to verify a series of items before authorizing the signing: the lien-free certificate (certificado de libertad de gravamen), the identity of the parties, their legal capacity to contract, payment of the applicable taxes (such as the ISAI, the real estate acquisition tax, whose rate varies by state), and compliance with tax and utility obligations tied to the property.

Once registered in the public registry, the deed has effect against third parties, meaning it protects the buyer from future claims by other people who might assert rights over the property.

Key differences between the two documents

If you want to estimate in advance how much this last step will cost, you can use our closing costs calculator (escrituración), since the amounts vary considerably depending on the state and the value of the property.

When each one is used in the buying process

In a typical purchase transaction in Mexico, the approximate order is usually as follows:

1. Negotiation of terms (price, payment method, delivery date).
2. Signing of the private purchase agreement, with a down payment or deposit handed over.
3. Gathering of documentation: IDs, lien-free certificate, appraisal, and, where applicable, processing of the mortgage loan. Check our checklist of documents for buying a home so you don't miss any.
4. Notarial review and calculation of taxes and fees.
5. Signing of the public deed (final contract) before a notary.
6. Registration of the deed in the Registro Público de la Propiedad.

The private contract is useful when there is a reasonable gap between the meeting of the minds and the notarial signing, for example while a lien is being released, a loan is being approved, or administrative paperwork is being completed. It does not replace the deed, but it provides contractual certainty while the deed is being prepared.

Risks of relying only on the private contract

A common mistake, especially in informal transactions or between acquaintances, is to stick with only the private purchase agreement without moving on to the public deed. This creates several risks:

• The buyer does not appear as the owner in the Registro Público, so they cannot fully prove their right as against third parties.
• The seller could, in theory, sell the same property to someone else if there is no registry entry to prevent it.
• If the seller dies, the process of regularizing the property becomes more complicated and may involve the heirs.
• Formal mortgage financing normally requires a public deed, not just a private contract.
• In a legal dispute, the private contract offers fewer evidentiary tools than a notarial instrument.

Before signing any document, it is worth reviewing the property's lien-free certificate (certificado de libertad de gravamen) to confirm there are no mortgages, attachments, or other liens that could complicate the transaction down the road.

Frequently asked questions

Is a private purchase agreement legally valid?

Yes, it is valid between the parties who sign it, since it is a meeting of the minds. However, it does not transfer ownership or take effect against third parties, so it does not replace the public deed registered in the Registro Público de la Propiedad.

Is it mandatory to sign a boleto de compraventa before the deed?

It is not mandatory in every case, but it is highly recommended when there is a period between the initial agreement and the notarial signing, since it puts the agreed terms in writing and protects both parties during that time.

What happens if the seller backs out after signing the private contract?

It depends on the penalty clauses included in the contract itself. Typically, the contract provides for forfeiture of the down payment or compensation in favor of the buyer, but it is wise to have an attorney review these clauses before signing.

Can I get a mortgage loan with only the private purchase agreement?

Most financial institutions require you to reach the notarial stage to formalize the loan, since the mortgage guarantee must be registered together with the deed. The private contract can serve as initial support during the application, but it does not replace the notarial process.