The process of setting the tax rate for the Contribution on Goods and Services (CBS) applicable in 2027 has entered a new phase. On September 14, 2026, the Executive Branch submitted to the Federal Court of Accounts (TCU) the calculation proposal prepared by the Federal Revenue Service based on the methodology previously approved by the Court.
It will now be up to the TCU to perform the calculation and submit its findings to the Federal Senate by October 30. The Senate, in turn, will have until December 15 to establish, by resolution, the reference tax rate that will take effect on January 1, 2027.
The decision will therefore be made just a few weeks before the CBS begins to be collected, underscoring the need for companies to make the necessary contractual, operational, and systemic adjustments in advance—adjustments that do not depend on knowing the final percentage.
While the official calculation has not been released, documents published by the Goods and Services Tax Management Committee (CGIBS) provide insights into the assumptions considered in the implementation of the new system. Among these is a reference to a combined standard tax rate for the IBS and CBS of 27.91%, of which approximately 18.7% would correspond to the IBS and 9.21% to the CBS.
These percentages, however, serve solely methodological purposes and do not correspond to the tax rates officially applicable to taxpayers.
How were the benchmarks of 18.7% and 9.21% calculated?
These references are based on CGIBS Resolution No. 14/2026, published on July 31, 2026. Although its purpose is primarily budgetary, the resolution and its technical note set forth key premises for understanding the context in which the new tax system will be implemented.
To estimate IBS revenue in 2027, the CGIBS reconstructed the tax’s potential tax base based on observed ICMS and ISS revenue. Under this methodology, it adopted a combined standard tax rate for the IBS and CBS estimated at 27.91%, assigning an 18.7% share to the IBS .
The difference of approximately 9.21% implicitly corresponds to the portion of the CBS included in this projection. As mentioned, these percentages are used solely for methodological purposes and do not correspond to the tax rates officially applicable to taxpayers.
The technical note itself acknowledges the forward-looking nature of the estimate, which was prepared before the data needed to support the CBS’s official calculation became available, and acknowledges that variations may occur depending on the composition of the tax base and taxpayer behavior during the implementation of the new system.
Transitional IBS tax rate in 2027
Unlike the methodological benchmarks of 18.7% and 9.21%, the IBS tax rate applicable in 2027 is already set forth in Article 127 of the Act on Transitional Constitutional Provisions.
During this period, the IBS will be levied at a total rate of 0.1%, consisting of:
- 0.05%, corresponding to the state portion; and
- 0.05%, corresponding to the municipal portion.
Resolution No. 14/2026 neither establishes nor alters these tax rates. The document merely uses them, in accordance with the provisions already set forth in the Constitution, as a basis for estimating tax revenue for the next fiscal year.
Although reduced, the tax rate applicable in 2027 marks the start of actual collection of the IBS and requires taxpayers to be prepared to calculate, record, and report their state and municipal portions separately.
The layouts currently published for electronic tax documents already include specific fields for these two installments, which underscores the need to review tax settings and the systems used to issue and receive documents.
Monthly Calculation and Initial Payments
For the purposes of its budget estimate, CGIBS took into account the process for calculating and paying the tax as provided for in the tax legislation:
- The calculation period will be monthly;
- the balance of the IBS will be paid by the last business day of the following month; and
- After the revenue is collected, the total amount collected will be calculated and distributed to the states, the Federal District, and the municipalities.
Thus, taxable events occurring in January 2027 will be calculated and collected in February. The corresponding distribution to state and local governments and the withholding of the portion earmarked for CGIBS funding will take place later, beginning in March.
For this reason, although the tax applies to the entire year of 2027, the revenue estimate prepared by the Committee is based on ten months of actual tax collection, from March through December.
Estimated Revenue and Funding for CGIBS
Based on these assumptions, Resolution No. 14/2026 estimates that actual IBS revenue in 2027 will reach approximately R$ 5.15 billion.
The regulation also proposes allocating 50% of this amount to fund the CGIBS during the fiscal year, which corresponds to the limit authorized by Complementary Law No. 227/2026. This exceptional allocation is related to the initial structuring of the administration of the new tax and does not represent an increase in the tax burden borne by taxpayers.
Preparing for 2027
The short timeframe between the setting of the CBS tax rate and the start of its collection, combined with the introduction of the IBS—already scheduled for 2027—requires companies to begin taking steps now, regardless of whether the final rate is known.
Among other things, it is recommended to review:
- the determination of the state and municipal portions of the IBS;
- systems for issuing, receiving, and recording tax documents;
- integration among the tax, accounting, financial, and technology departments;
- the procedures for calculation, reconciliation, and collection;
- the potential impacts on contracts, prices, and cash flows; and
- the mechanisms for contract updates and pricing adjustments following the announcement of the final CBS rate.
The tax team at Araújo e Policastro Advogados remains available to assist in assessing the impacts of the Tax Reform and in preparing for the start of IBS and CBS collection in 2027.
Authors:
Fernanda Botinha Nascimento – fnascimento@araujopolicastro.com.b
Priscila Santos Rosa – prosa@araujopolicastro.com.br