The Taxable Events of Consumption Taxes in Light of Private Law Structures

Abstract

This article aims to examine the definition of the taxable event (materiality) of the IBS (Goods and Services Tax) and the CBS (Contribution on Goods and Services), from the perspective of the interaction between these taxes and the concepts, institutions, and structures of Private Law. The study seeks to determine whether the materiality defined by Constitutional Amendment No. 132/2023 and by Supplementary Law No. 214/2025 requires a necessary connection between the incidence of the IBS and CBS and the execution of legally valid acts or transactions governed by Private Law. In the first part, the analysis focuses on the taxable event as defined by the Supplementary Law, concluding that the legislator chose to characterize the taxable event as a “factual situation.” The second part examines the compatibility of this definition with the constitutional materiality of those taxes, concentrating on the interpretation of the term “operations” as employed by the derived constituent power. The investigation concludes that constitutional materiality is not limited to “legal situations,” that is, it does not require the performance of acts or transactions validly constituted under Private Law. Accordingly, from the perspective adopted in this study, it is concluded that the supplementary legislator did not exceed the boundaries established by the derived constituent authority.