YEAR 2015 N.º 3

ISSN 2182-9845

Substance over form: anti avoidance clauses and the legality of tax planning

Eva Dias Costa


Freedom; neutrality; avoidance; anti-abuse clauses


The principle of private autonomy is a result of the will theory in contracts, and emanates directly from the most basic principle of Human freedom. 
It is true that the obligations are born ex lege; however there is always some intervention of the human will. The tax payer can in fact choose the way he wants to conduct his business – or if he wants to conduct it at all -, and such choice may take into account tax considerations.
Therefore, the law recognizes that the individual is free to elect between two or more possible legal configurations despite of tax considerations, that is, even if the one he prefers means paying less tax.
Arguably, the option can be dictated by the fact that is it isa measure of paying less tax, provided it is not a mere subterfuge or a tax avoidance fraudulent scheme.
We will occupy ourselves with the limits of this freedom, as well as focusing on the dangers posed by the substance over formtheory, and its articulation with the nullum tributum sine lege certa et stricta principle.