From what time will interest be incident on the collection of differences in rent determined in renewal and review actions?

Article 69 of the Leasing Law establishes that the rent set in a decision is retroactive to the service of process and the differences due, having discounted the rent already settled, will be paid having been corrected, being payable when the decision that sets the new rent has become final and unappealable.

Despite the clarity of the legal text in question, there are still doubts about the formula to calculate the collection of rental differences in renewal and review actions, especially with respect to the application of interest rates: should they be calculated from the service of process, the decision that set provisional rent, the decision on the merits, or when the decision has become final and unappealable?

For a time the Superior Court of Justice has been adopting the understanding that arrears interest on the differences between the amounts of the original rent and that fixed in a renewal or review action will be counted from the service of process in a collection action, and it should be mentioned that, with the advent of the Code of Civil Procedure of 2015, differences in rents will be determined at the enforcement stage.

This understanding was constructed taking into account that in the course of a renewal or review action, the lessee paid the rent on a regular basis (original, or provisional), there being no need to talk about arrears, it being the case that the obligation to pay the differences only arose from the time the decision became definitive.

In fact, it is unreasonable to admit that interest is incident before the decision has become final and unappealable because, in addition to the lack of arrears, the new rents have not yet been definitively set, and there is a possibility that the decision may be altered with respect to such amounts.

The only conclusion that is reached, therefore, is that arrears will only be due from the notification to pay differences in rent at the enforcement of decision stage, since the mora solvendi is due to the lack of timely payment by the debtor, being typified by the concurrence of three factors, namely, the enforceability of the obligation, noncompliance with it and constitution of arrears (Caio Mário Pereira da Silva, “Instituições de Direito Civil” [Institutions of Civil Law], v. II, 21st edition, page 343).

In other words, in order for the arrears to be recognised, it is essential that the obligation be payable, which will only takes place when the decision has become final and unappealable, at the enforcement stage, and when the lessee has been notified to pay the calculated differences.

Without this, there is no need to speak of interest being incident on the collection of the difference in rents.