The New CTN | A new relationship between tax authorities and taxpayers? Binding precedents in the new CTN: can the tax authorities still collect what the STF and STJ have already decided?

Binding precedents in the new CTN: can the tax authorities still collect what the STF and STJ have already decided?

If a tax dispute has already been resolved by Brazil’s Federal Supreme Court (STF) or Superior Court of Justice (STJ) through a decision with binding effect, why should taxpayers keep bearing the costs of litigating it with the tax authorities?

The question is not merely theoretical.

Companies often have to mobilise financial resources, internal teams and legal counsel to contest tax claims whose legal basis has already been rejected in rulings by the higher courts.

Complementary Law No. 236/2026 seeks to address this problem by expressly establishing in the National Tax Code (CTN) that certain binding judicial decisions must also guide the conduct of the Tax Administration.

The change seems natural. Its consequences, however, may be more significant than they appear.

Mandatory precedents did not begin with Complementary Law No. 236/2026

Observance of judicial precedents is nothing new in Brazilian law. The Code of Civil Procedure (CPC), particularly Article 927, already sets out situations in which judges and courts must follow qualified decisions and case-law guidance, such as STF decisions in concentrated constitutional review, binding summary statements (súmulas vinculantes) and rulings on repetitive appeals.

In the federal tax sphere, Articles 19 and 19-A of Law No. 10,522/2002 already provided mechanisms to release the Office of the Attorney General of the National Treasury (PGFN) from filing certain briefs and appeals, and to prevent tax credits from being constituted in situations specified by law.

The problem, therefore, was not really the absence of tools for observing precedents, but their effective and uniform incorporation into the work of the tax administrations, especially in a federal system in which the Federal Government, the States, the Federal District and the Municipalities have their own structures for audit, adjudication and collection.

It is in this context that Complementary Law No. 236/2026 introduces a significant change.

Observance of binding precedents no longer depends solely on specific mechanisms in procedural legislation or in the laws of each taxing entity, and now expressly forms part of the general rules of the CTN.

The new Article 194-A: judicial decisions also bind the Tax Administration

The new Article 194-A of the CTN provides that, once a final decision of the STF or the STJ with binding effect in the judicial sphere becomes res judicata, it will also bind the Tax Administration. This provision carries an important legal consequence: judicial guidance that meets the legal requirements cannot simply be disregarded by the tax authority.

But the innovation goes beyond recognising this binding effect. The provision requires the Public Treasury, within a maximum of 90 business days from the date the decision becomes final, to publish, by means of a reasoned legal opinion, how it will apply the judicial guidance.

This opinion must address the application of the precedent to tax and customs credits, the matters on which the Treasury will no longer contest taxpayers’ claims, and those in which it will withdraw objections or appeals already filed.

This is not merely a matter of recognising that a given decision must be respected, but of requiring the Administration to explain how that recognition will be incorporated into its conduct.

The legal opinion provided for in Article 194-A is an instrument of transparency and implementation of the precedent. It is not, however, the act that creates its binding force, which derives directly from the law once the relevant requirements are met.

The reform also requires the development of management tools and periodic guidance for public officials on judicial and administrative precedents.

The aim seems clear: to narrow the gap between what the higher courts decide and what the tax authorities actually do.

Can the tax authorities keep issuing assessments on matters already decided?

Perhaps the most significant aspect of the new rules lies in the consequences attributed to precedents favourable to taxpayers.

Article 208-G of the CTN sets out the situations that are binding in administrative tax proceedings, including the STF’s binding summary statements, final decisions rendered under the general repercussion and repetitive appeals systems, and STF decisions in concentrated constitutional review.

The provision also covers resolutions of the Federal Senate suspending the enforcement of laws, as provided for in the Constitution, and summary statements resulting from repeated and uniform decisions of the administrative tribunals, within the respective federative entities.

Its main practical innovation lies in paragraph 1. The rule provides that no infringement notices or tax assessment notices should be issued, no objections, refund requests or appeals should be dismissed, and no credits should be entered in the register of overdue tax debts (dívida ativa) where their constitution is based on a matter decided in the taxpayer’s favour under the terms of the provision.

The difference is significant. Instead of requiring taxpayers first to be assessed and then to demonstrate, in administrative or judicial proceedings, that there is a binding precedent favourable to their position, the new rules seek to prevent certain tax claims from being raised in the first place.

Precedent no longer functions only as grounds for a defence against collection and now guides the administrative decision on whether collection is possible at all.

If properly applied, the change will help prevent companies from having to repeatedly litigate legal issues already resolved with binding force.

Not every STF or STJ decision prevents collection

Applying the new rules, however, calls for caution.

Complementary Law No. 236/2026 did not establish that any decision favourable to the taxpayer, issued by the STF or the STJ, will automatically prevent tax enforcement action. It is necessary to identify the nature of the judicial ruling, its binding force, the scope of the thesis established and how it corresponds to the specific situation, taking into account any modulation of effects and particular circumstances that may justify different treatment.

A decision on whether a given tax applies, for example, does not necessarily rule out claims relating to transactions, periods or legal situations not covered by its determining grounds.

Likewise, the existence of a favourable precedent does not in itself mean that all amounts previously paid must be automatically refunded, or that cases already closed with final decisions will be reopened.

What the new legislation seeks to prevent is the Administration’s insistence on an interpretation incompatible with a binding decision that actually applies to the dispute.

And when the dispute is still being decided?

The reform also addressed situations in which the legal question has not yet been finally resolved.

The new Article 208-J provides for the automatic stay of administrative tax proceedings that discuss the same legal question whenever the STF or the STJ has ordered the collective suspension of court cases so that the question can be resolved through a qualified precedent.

The provision seeks to prevent administrative proceedings from producing decisions on disputes whose solution is being standardised by the higher courts. However, this is not an indiscriminate suspension of every proceeding related to the subject. The rule depends on the legal requirements, in particular an order for collective suspension and the identity of the legal question.

There are, therefore, two complementary dimensions: avoiding conflicting administrative decisions while the judicial outcome is pending, and requiring observance of the binding precedent once the requirements for its application are met.

Can the change already be enforced against the tax administrations?

Complementary Law No. 236/2026 came into force on 4 September 2026. However, not all of its provisions follow the same implementation regime.

Article 211-B gives the Federal Government, the States, the Federal District and the Municipalities two years to adapt their tax and customs legislation to the parameters of Articles 208-A to 208-J, which concern administrative tax proceedings.

The provision further states that, in the absence of such adaptation, these rules will apply until specific legislation is enacted that complies with the minimum parameters of the CTN.

This framework requires two aspects to be distinguished: on the one hand, Article 194-A, which establishes that the Tax Administration is bound by the judicial decisions it covers, is not included in the adaptation period provided for in Article 211-B; on the other, the implementation of the specific commands of Article 208-G must be examined in light of the transition regime and the legislation applicable to each federative entity.

It would not be appropriate to state that all the new procedural consequences apply immediately and uniformly, just as it does not seem correct to interpret the adaptation period as a general authorisation to disregard binding precedents for two years.

How these provisions fit together may itself become the subject of new disputes.

What changes for businesses?

For companies with significant tax litigation, the changes deserve attention that goes beyond monitoring the decisions of the higher courts.

The existence of a favourable binding precedent may affect the assessment of infringement notices, ongoing administrative proceedings, refund requests and credits sent for collection.

It will be necessary to check whether the thesis actually covers the transactions under discussion, which periods are included, whether there has been any modulation of effects and at what stage the administrative procedure stands.

It will also be important to monitor how the tax administrations publicise precedents and incorporate their guidance into internal procedures.

This may have a direct impact on the management of tax liabilities, risk assessment and the definition of companies’ defence and regularisation strategies.

After all, litigation is a cost that goes beyond legal fees or court expenses. It involves time, guarantees, administrative appeals and uncertainty about obligations that may affect important business decisions.

Legal certainty also has an economic dimension.

Can the tax authorities still collect what the STF and STJ have already decided? The answer depends on the nature of the judicial decision, its binding force and whether it actually applies to the specific case.

But Complementary Law No. 236/2026 sets out an important guideline: when the dispute has already been resolved by a binding precedent covered by the legislation, the Tax Administration cannot simply ignore it and insist on the rejected interpretation.

The main innovation may lie less in recognising the authority of the higher courts’ decisions than in seeking to ensure that their precedents have consequences for the day-to-day conduct of the tax authorities, before the dispute turns into a new assessment, appeal or tax enforcement action.

This does not eliminate tax audits, does not prevent the collection of taxes lawfully due and does not dispense with examining the particular circumstances of each situation.

It does mean, however, recognising that the obligation to observe the law also requires the Tax Administration to be consistent with the binding interpretations established by the competent courts.

It remains to be seen whether this guidance will actually be incorporated into administrative practice, or whether taxpayers will continue to need to go to court to have rights already secured by binding precedents recognised.

This may be one of the most important tests of the new relationship between tax authorities and taxpayers proposed by the CTN reform: not only ensuring that a dispute can be resolved, but preventing it from being needlessly reproduced.

And if the new CTN seeks to avoid disputes that have already been settled, another question arises: will the guarantees of administrative tax proceedings also become truly uniform across the country?

That will be the subject of the next article in the series.