«As Regina Santos Pereira, a Partner at SRS Legal, explains, there are two cases in which the coefficient for updating rents does not apply: residential and non-residential residential and non-residential rental contracts that contain an express clause on how the rent will be updated (for example, a fixed percentage); and the so-called old rents, or, more specifically, housing contracts entered into before 1990 that have already been updated in the context of the New Regime do Arrendamento Urbano (NRAU), which has resulted in an increase in the in line with the tenant's corrected annual income.
(...)
Only in cases where the requirements described above have not been met by the landlord can the tenant object to the application of the coefficient for updating the rent. "If, after the tenant's opposition, the conflict remains, the tenant may be justified in depositing the rent for his defence," says Regina Santos Pereira.
In practice, this means that if the landlord wants to apply the coefficient for updating the rent, there is no way of avoiding it. "The law doesn't provide for any form of negotiation between landlord and tenant regarding the application of coefficients, so if the landlord complies with all the legal requirements, the tenant will be obliged to accept the new rent," summarises the lawyer specialising in civil procedural law.»