Most real estate transactions in Mexico have at least two contracts: First, an offer of acceptance (oferta) and/or a promissory agreement (contrato de promesa), and second, a purchase-sales agreement (contrato de compraventa). The first two agreements are preliminary agreements containing the basic transactional information. They are not the instruments by which title to the property is transferred to the buyer. The second contractual document is the agreement to be protocolized by the notario that will transfer title to the buyer. This document may have several different forms:--a real estate trust agreement (contrato de fideicomiso), a reserve title agreement (contrato de compraventa con reserva de dominio) or an assignment of real estate trust rights (contrato de cesion de derechos fideicomisarios).
The Civil Code defines an agreement (convenio) as an accord (acuerdo) between two or more persons to create, transfer, modify or extinguish obligations. Specifically, the Civil Code defines a contract as an agreement that produces or transfers obligations and rights. In general, real estate contracts in Mexico must be "protocolized" before a notary public and, to be binding on third parties, they must be filed with the public registry of property. Once there is a written acceptance to the offer, it is recommended that the buyer's attorney draw up the sales contract or promissory agreement. Since this agreement is the single most important document the buyer will execute with the seller, and the agreement's contents will determine the terms and conditions of the transaction, the buyer should insist that his attorney perform this responsibility.