Damage mitigation in Brazilian Law

between the creditor's burden and the concept of unjust demage

Abstract

Originating from common law, the "duty to mitigate the loss" theory states that, in the event of a default, the creditor must take reasonable steps to minimize their own losses, otherwise they risk losing the avoidable portion of the compensation. In Brazil, this theory became widely applied after Enunciado 169 of the CJF, which linked it to the principle of good faith. However, this linkage suggests the norm has the legal nature of a duty, implying a debtor could judicially demand that the creditor take measures to mitigate their own damages. As this scenario is considered unreasonable, the norm is better understood as having the legal nature of a burden, because the creditor's inaction results only in the partial loss of compensation, without further consequences. In light of this apparent incongruity—a norm with the nature of a burden being linked to an obligation—this work seeks to ground the mitigation theory in the concept of unjust damage. Through bibliographic research and the deductive method, the study concludes that civil liability accommodates this theory: in cases where a creditor intentionally allows damage to occur or worsen, the absence of "unjust damage" renders the loss lawful and, therefore, precludes compensation.