In a decision of great repercussion, the Federal Supreme Court understood that res judicata may be reviewed in tax matters, also deciding, to the surprise of the market, that the effects of such decision cannot be modulated, which means retroactive collection of taxes.

The Ministers in the case ruled unfavorably to the taxpayers that had a final and unappealable favorable decision allowing the non-payment of Social Contribution on Net Profits (CSLL). They will be required to pay the tax since 2007, when the Court changed its previous understanding of the matter and recognized the constitutionality of the contribution in the judgment of a Direct Unconstitutionality Action.

This result originated from the judgment of two extraordinary appeals that discuss the limits of res judicata in tax matters, RE 949.297 and RE 955.227, listed under Themes 881 and 885 of the general repercussion subjects of the STF.

It was unanimously decided that a taxpayer that obtained a final and unappealable favorable court decision allowing the non-payment of a tax automatically loses its right in the face of a new understanding of the STF that considers the collection constitutional in a concentrated control judgment (ADIN or with general repercussion). The understanding is that the termination of the effects of res judicata is automatic upon a new decision of the STF of this nature, and it is not necessary for the Federal Government to file an action for revision or rescission.

As for the modulation of effects, the STF denied the request made by the taxpayers, whose purpose was that the decision would only take effect as of the publication of the minutes of the judgment on the merits of the appeals, which, in practice, would allow the Federal Government to collect the tax only as of 2023. However, with the denial, the collection may be retroactive, for example, to 2007 in the case of CSLL.

Moreover, on the other hand, the STF has understood that if the outcome of a certain trial concludes that the tax in question is constitutional, the start of the collection must respect the annual and nonagesimal anteriority, depending on the tax. In the case of CSLL, for example, only the noventene applies.

With this judgment, the following theses were established:

1. The decisions of the STF in incidental control of constitutionality, previous to the institution of the general repercussion regime, do not automatically impact the res judicata that has been formed, even in tax legal relations of successive tract.
2. On the other hand, decisions handed down in direct actions or general repercussion decisions automatically interrupt the temporal effects of final and unappealable decisions in such relations, respecting the principle of non-retroactivity, annual anteriority and the noventene or nonagesimal anteriority, depending on the nature of the tax.The decisions of the STF in incidental control of constitutionality, prior to the institution of the general repercussion system, do not automatically impact the res judicata that has been formed, even in successive tax legal relations.