Test Rates in 2026 and 2027: How the Tax Reform Pilot Phase Works
Understand the 2026 and 2027 test rates. What is tested, who participates, and the legal implications of the pilot phase.
Executive Summary
LC 214/2025 sets out a two-year period (2026-2027) in which CBS and IBS operate with test rates before the definitive values are set. For the tax lawyer, understanding the legal framework of this pilot phase is essential to advise clients and challenge any overreach by the Federal Revenue Service. Vivian Sampaio explains the legal contours of the experimental rates.
Legal Framework of the Test Rates
Constitutional basis
The pilot phase is provided for in Article 7 of LC 214/2025, which allows the IBS and CBS Steering Committee to establish experimental rates for a two-year period in order to collect real revenue-collection data.
The operational details of this phase depend on supplementary regulation and on the acts of the Steering Committee, which is why continuous regulatory monitoring is indispensable.
Legal nature of the test rates
The test rates are not merely illustrative — they have a binding legal effect on taxpayers participating in the pilot. This means that:
- Paying CBS and IBS based on the test rates is mandatory.
- Credits generated during the pilot are valid and usable.
- Litigation over the pilot phase will be assessed in light of the principle of public good faith.
Allocation of the proceeds
The proceeds from the test rates are already allocated to the State and Municipal Participation Fund (FPE/FPM) under the rules of the new system — there is no segregation or reserve for future adjustments.
What Is Being Tested
CBS rates
The Contribution on Goods and Services is being tested with rates within a band defined for the transition period. The goal is to verify:
- The elasticity of the contribution base.
- The sector-specific impact of the levy.
- The market’s reaction to different levels of tax burden.
In practice, the pilot seeks to calibrate revenue collection, credit generation, and operational execution before the permanent reference rates are set.
IBS rates
The Tax on Goods and Services also operates with test rates. Aspects being tested:
- The levy on internal vs. interstate transactions.
- The behavior of revenue collection across different states.
- The interaction between IBS and CBS in forming the final price.
In the case of IBS, the emphasis falls on destination-based distribution, reconciliation among governmental entities, and measuring the sector-specific impact during the transition.
Split payment mechanism
One of the most important variables being tested is the effectiveness of split payment — the automatic separation of the tax amount at the moment of payment. The pilot phase includes:
- Transactions in a test environment with split payment active.
- Verification of the success rate of automatic separation.
- Analysis of cases of non-payment in tax collection.
Who Participates in the Pilot
Selection criteria
Article 8 of LC 214/2025 establishes the criteria for participation in the pilot:
- Revenue: Companies with annual gross revenue above R$ 4.8 million.
- Tax regime: Those opting for Lucro Real (actual-profit regime) or Lucro Presumido (presumed-profit regime).
- Strategic sectors: defined in regulation by the Ministry of Finance to broaden the collection of sector-specific data.
- Voluntary participation: Companies may apply voluntarily by registering on the Federal Revenue Service website.
Obligations of participants
Companies in the pilot have specific obligations:
- Issue tax documents with CBS and IBS itemized at the test rates.
- Submit a monthly transaction report to the Steering Committee.
- Maintain separate bookkeeping for the two systems (old and new).
- Allow the Committee to audit the data collected.
Rights of participants
Participants in the pilot also have protected rights:
- A guarantee that no penalties will be applied for bookkeeping errors during the adaptation phase (within reasonable parameters).
- The right to use the CBS and IBS credits generated in the period.
- The right to clear information about rate changes before each fiscal year.
Relevant Legal Aspects
Legality of the test rates
Is a tax created by an LC (supplementary law) constitutional? Yes, in line with the settled case law of the STF on the creation of taxes by supplementary law. Test rates within the band established by the LC are also constitutional.
The principle of legality and rates
The central question: do rates set by administrative act (a Steering Committee ordinance) respect the principle of legality?
Vivian Sampaio’s position: The test rates fall within the band established by LC 214/2025, which means the Executive has a legal margin to set them within those parameters. There is no violation of the principle of legality because the supplementary law has already set the limits.
Even so, the matter may be litigated if taxpayers consider that the legal limits were exceeded or that strict legality was offended.
Legal criticisms of the model
Some legal scholars point to three recurring criticisms of the model:
- Creating a test period with tax effects may strain the principle of legal certainty.
- The absence of a transparent methodology for adjusting rates may give rise to questions about due process.
- The mandatory participation of companies without adequate compensation may be argued to be excessive.
The tax lawyer should be aware of these criticisms in order to advise clients who wish to challenge them.
Implications for Litigation
Errors in applying the test rates
If a company makes an error in applying the test rates during the pilot, what is the legal treatment?
LC 214/2025 establishes that good-faith errors do not generate penalties during the pilot phase, but they do create an obligation to top up the payment. The lawyer should advise the client to:
- Self-correct before any notice is issued.
- Document all errors and corrections made.
- Keep proof of payment and of communications with the Federal Revenue Service.
Appeals against Steering Committee decisions
Are decisions by the CBS/IBS Steering Committee on rates and pilot participation subject to appeal?
The appeal path depends on the procedural regulation and on the acts of the Steering Committee, with a case-by-case assessment of the administrative sphere and any eventual litigation.
Advising the Client During the Pilot
Contract analysis
The lawyer should review contracts signed by the client to check whether they include a rate-variation clause. Long-term contracts without such a clause may give rise to disputes when the definitive rates differ from the test rates.
Tax planning
During the pilot, it is already possible to do tax planning based on real CBS and IBS data. The lawyer should:
- Analyze the effective tax burden per transaction.
- Identify opportunities to reorganize the business in order to reduce impact.
- Model scenarios for different levels of definitive rates.
Contingencies
If the client receives assessments related to the pilot, the lawyer should verify:
- Whether the company was correctly classified as a pilot participant.
- Whether the rate applied was within the band informed for the period.
- Whether the Federal Revenue Service flagged any divergence regarding the calculation methodology.
Next Steps
The 2026-2027 pilot phase is a period of data collection — but also of legal preparation. The lawyer who understands the legal framework of the test rates is better positioned to advise clients and anticipate questions that may become litigious in the future.
Want to understand how the tax reform pilot phase affects your client’s strategy? On /napratica, VMAHUB publishes guides for tax law professionals. For a tailored analysis of the situation, talk to our team: [email protected]
Read also:
Sources: LC 214/2025; STF — Case law on the legality of rates; Federal Revenue Service — Regulation of the CBS/IBS Steering Committee.
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