Anteriority Principle — annual and 90-day non-retroactivity
The anteriority principle is a constitutional rule (article 150, III, "b" and "c" of the Brazilian Federal Constitution) that prevents the government from collecting a tax in the same fiscal year (annual anteriority) or within 90 days (nonagesimal anteriority) of the law that created or increased it. It protects taxpayers from tax surprises.
Two cumulative rules
- Annual anteriority (article 150, III, "b"): a tax can only be collected in the fiscal year following publication of the law. A law published on any date in 2026 only takes effect from January 1, 2027.
- Nonagesimal (90-day) anteriority (article 150, III, "c"): a tax can only be collected 90 days after publication. A law published on November 15, 2026 only takes effect in mid-February 2027.
The two rules are cumulative — the date FURTHEST in the future prevails. Example: a law published on December 15, 2026 only takes effect from March 15, 2027 (because the 90-day rule falls later than the following fiscal year).
Constitutional exceptions
Some taxes have their own rules:
- Exceptions to annual anteriority: import duty (II), export duty (IE), federal excise (IPI), tax on financial operations (IOF), compulsory loans for war/calamity, CIDE on fuels, and ICMS on fuels.
- Exceptions to the 90-day rule: import duty (II), export duty (IE), income tax (IR), tax on financial operations (IOF), compulsory loans for war/calamity, and the tax base of municipal property tax (IPTU) and motor vehicle tax (IPVA).
Income tax (IR) has a peculiarity: it is NOT subject to the 90-day rule, BUT it is subject to annual anteriority. A law published on December 31, 2026 may take effect on January 1, 2027 with respect to income tax.
The Brazilian Tax Reform (CBS/IBS) has specific transitional rules (phased rollout from 2026 to 2033) that respect anteriority in their introduction.
Frequently asked questions about the anteriority principle
If a law is published on December 31, can the tax be collected on January 1?
It depends. If it complies with both annual anteriority (taking effect in the following fiscal year) AND the 90-day rule, it can be collected. Because both are cumulative, a law published on December 31, 2026 satisfies annual anteriority (effective from January 1, 2027) but does NOT satisfy the 90 days — so effective collection is postponed to April 1, 2027.
Does a tax increase have to respect anteriority?
Yes. The principle applies to the CREATION and the INCREASE of taxes (not just creation). A rate increase, an expansion of the tax base, or a reduction of an exemption are all subject to anteriority. Monetary restatement is not considered an "increase" (STJ Precedent 160).
How can a violation of anteriority be challenged?
Through the courts: a preventive writ of mandamus (mandado de segurança) where collection is threatened, or a declaratory action / action for recovery of overpaid tax where payment has already been made. Courts have suspended collections that violate the principle, with retroactive effect (refund of amounts unduly paid). A typical case: immediate collection of an increase without observing the 90-day period.
Did the Brazilian Tax Reform respect anteriority?
Yes. Constitutional Amendment 132/2023 and Complementary Law 214/2025 establish a phased schedule (a 0.9% test rate in 2026, full CBS in force in 2027) that respects anteriority — companies have a reasonable period to adapt. Specific disputes over rates regulated later may arise on a case-by-case basis.