ISABI is the tax on acquiring real property
ISABI is the commonly used Spanish abbreviation for the tax on the acquisition of real property. In a typical purchase, it is normally a buyer-side closing cost addressed through the notarial process under the rules applicable to the property and transaction.
For 2026, the municipal tax laws of Baja California Sur’s five municipalities—La Paz, Los Cabos, Comondú, Loreto, and Mulegé—provide a general 3% rate for the acquisition of real property. That does not mean the final tax is simply the purchase price multiplied by 3%. The amount depends on the legally applicable taxable base, the applicable rules, and the facts of the property and transaction.
What value is used for the calculation?
The taxable base is the value legally used to calculate the tax. A buyer should not assume that the purchase price alone determines that value. Depending on the applicable rules, relevant information may include the transaction value, appraisal information, cadastral information, or another legally applicable measure.
The notary reviews the applicable information and determines or confirms the tax treatment and amount within the notary’s authority and the applicable rules. A published rate or general example cannot replace the calculation for the specific property and transaction.
When is ISABI paid?
ISABI is normally addressed as part of the applicable notarial closing process. The notary confirms the treatment and amount based on the transaction information and the applicable rules.
ISABI is one specific category within the total closing costs. It should be distinguished from applicable notarial, registration, trustee-bank, technical-document, translation, escrow, and closing-coordination costs.
Why can the estimate change?
An estimate may change when relevant information is confirmed or changes, including property information, value, appraisal or cadastral information, the transaction date, transaction circumstances, or the applicable rules.
The Closing Company organizes cost information, communicates updates, and distinguishes confirmed amounts from estimates and figures still awaiting confirmation. Final tax treatment and calculation remain with the notary and competent authorities. Independent tax advice may be appropriate when a transaction has unusual circumstances.