The Civil Code defines usufruct (usufructo) as a real right consisting of the power to enjoy a thing on condition of preserving its form and substance and returning it to its owner (Art. 823). It involves two coexisting rights, that of the bare owner (nudo propietario) and that of the usufructuary, and it has a limited duration, at the end of which it passes to the bare owner and consolidates with the ownership (Art. 824). It is created by law, by will, by gift, sale or another act between living persons, or by prescription (Art. 825). If it concerns real estate by an act between living persons, it is not valid unless granted by a registered public instrument (Art. 826). It may be for a fixed term or for the whole life of the usufructuary, and if no term is set it is understood to be for life (Art. 829). Bare ownership (nuda propiedad) may be transferred by act between living persons and transmitted by reason of death, whereas the usufruct cannot be transmitted by will or on intestacy (Art. 832).
On the tax side, the Tax Statute sets a special valuation rule for gratuitous acts that generate occasional gain (gifts, inheritances and legacies, Art. 302): under Article 303, item 11, a lifetime usufruct is valued at 70% of the value of the asset, a temporary usufruct at 5% for each year of duration without exceeding 70%, and bare ownership is the difference. In addition, paragraph 3 of that article provides that no occasional gain is generated by reason of the consolidation of the usufruct in the bare owner. Those rules explain why usufruct is used in estate planning. But they do not turn the mechanism into a shield: the usufruct can be attached by the usufructuary's creditors (Civil Code, Art. 862), bare ownership answers for its owner's debts (Civil Code, Art. 2488), and acts carried out to the detriment of creditors can be challenged.