Form and Substance in Tax Law

This book defines the substance over form doctrine in Tax Law and sets clear limits on its application within the Brazilian Constitutional Tax System. Grounded in Brazilian constitutional principles and illustrated with case examples, the analysis develops a general framework that is extensible to other liberal democracies, testing the doctrine’s compatibility with constitutional principles while delineating boundaries for legitimate use. Drawing on a paradigmatic case from Brazilian Tax Law, Chapter One offers a precise definition of the substance over form argument and examines each component to distinguish it from accounting based approaches to taxation, debates on the relationship between Tax Law and Private Law, the defeasibility of tax rules, the rejection of qualification nominalism, and the principle of material truth; it also maps points of contact with interpretations of “form” as requirements for the existence or validity of legal transactions or as essential elements of those transactions, and presents multiple examples of the doctrine’s use in Brazilian Tax Law. Chapter Two critically refutes three common justifications for the prevalence of substance over form in Brazil—broad notions of simulation, the principle of contributive capacity, and economic substance—and then analyzes eight constitutional principles that favor a priori formal qualification criteria in tax matters: the rule of law, democracy, separation of powers, legality, legal certainty, human dignity, freedom, and equality. Chapter Three outlines practical limits on substance over form arguments by identifying preference rules for resolving conflicts among qualification criteria for facts, acts, and legal transactions in Brazilian Tax Law—whether in “form versus form” or “form versus substance” structures—thus providing a rigorous, constitutionally grounded roadmap for courts, tax authorities, and practitioners focused on Brazilian Tax Law, the Constitutional Tax System, economic substance, formal qualification, and legal certainty. Chapter Four compares the definition and criteria for applying the substance-over-form argument, as established in light of examples from Brazilian Tax Law, with key cases of this argument’s application in other countries. The aim is to outline, even if only preliminarily, the limits of the applicability of the theses presented in this work to other legal systems.