The Supreme Court Declares Mexico City’s Real Estate Acquisition Tax Rate Unconstitutional: What Those Who Acquired Real Estate in 2024 Need to Know

The Plenary of Mexico's Supreme Court of Justice (SCJN) issued binding precedent P./J. 196/2026 (12a.), digital registration number 2032742, declaring Article 113 of the Mexico City Tax Code, as in force in 2024, unconstitutional. The provision established the rate schedule for the Real Estate Acquisition Tax (ISAI).

The Supreme Court held that the schedule violates the constitutional principle of tax proportionality because its structure does not ensure that the tax increases progressively in line with property values. The combination of tax brackets, fixed amounts and applicable percentages may produce outcomes in which a lower-value property is subject to a higher tax than a more valuable property.

The precedent, which is binding on courts throughout Mexico, expressly concerns the legislation in force in 2024 and provides grounds for assessing potential legal challenges to ISAI payments calculated under that schedule.

Individuals and companies that acquired real estate in Mexico City during that year should review their transactions and seek specialized advice regarding the availability of constitutional relief through amparo proceedings and the applicable filing deadlines. Depending on the circumstances, a successful challenge could result in the schedule being disapplied and, where appropriate, a refund of excess tax payments.

The precedent does not automatically entitle taxpayers to a refund. Transactions from other fiscal years require a separate assessment of the applicable legislation to determine whether similar issues arise.