October 2026
One of the key developments in the first half of October was a ruling by the 2nd Public Treasury Court of Santos, São Paulo, excluding the IBS and the CBS from the tax base of the ICMS. Reportedly the first judgment on the merits addressing this issue, the decision departs from the position previously expressed by the São Paulo State Tax Authorities in a formal tax consultation ruling.
During the same period, it was confirmed that the provisional measure setting the rates of the Excise will only be issued after the elections, which prevents the tax from being charged from January 1, 2027. Meanwhile, the deadline is approaching for the Federal Court of Accounts (TCU) to send the Federal Senate its calculation of the CBS reference rate, amid discussions about a possible postponement of the tax reform or changes to its implementation schedule.
This edition also covers the announcement that payment by the buyer will be automated from 2027, the first data released by the Federal Revenue Service on the CBS being shown on tax documents, and the end of the deadline to join the Simplified National Tax Regime (Simples Nacional) for next year.
Below, we summarize the main developments of the period and their possible effects on taxpayers.
Santos court excludes IBS and CBS from the ICMS tax base
Writ of Mandamus No. 1005586-56.2026.8.26.0562, 2nd Public Treasury Court of Santos, decision of October 9, 2026
The 2nd Public Treasury Court of Santos partially granted a preventive writ of mandamus to exclude, from 2027, the IBS and the CBS from the ICMS tax base. This is the first decision on the merits in favor of taxpayers on this issue.
The lawsuit was filed in response to the position of the São Paulo State Department of Finance, especially in Tax Ruling No. 32,931/2025, that the IBS and the CBS, once they are actually charged, must be included in the ICMS tax base because they are part of the transaction value. According to the court, this administrative position represents a concrete threat to the taxpayer’s rights, which justifies a preventive lawsuit.
On the merits, the court held that the IBS and the CBS are calculated “on top of” the price and are not the taxpayer’s own revenue, since these amounts only pass through the company’s accounts until they are paid to the government. On this basis, it concluded that including the new taxes in the ICMS tax base would be incompatible with the constitutional and legal framework of the tax reform.
Although the decision applies only to the company that filed the lawsuit, it is a favorable precedent for taxpayers on this issue. The decision is subject to mandatory review by the São Paulo State Court of Appeals and, according to press reports, the State Attorney General’s Office said it intends to appeal.
Impact. Including the IBS and the CBS in the ICMS tax base could increase the tax burden on transactions during the transition period of the tax reform, until the state tax is abolished in 2033. Although this is not yet a settled position of the courts, the decision is a favorable precedent for taxpayers and reinforces the trend of litigation on this issue, especially given the position already formally adopted by the São Paulo tax authorities.
Excise Tax collection is not expected to start on January 1, 2027
Statements by the Minister of Finance released in October 2026 and Article 150, III, “c”, of the Federal Constitution
In our previous edition, we reported that the provisional measure setting the Excise Tax rates had not yet been published, even though the deadline to allow the tax to be charged from January 1, 2027, under the 90-day rule, ended in early October.
The postponement was confirmed by the Minister of Finance, Dario Durigan, who announced on October 8 that the government intends to send the provisional measure to Congress only after the second round of the elections, which will be held on October 25, 2026. According to the minister, an agreement has already been reached with the economic sectors affected by the new tax.
According to the information released, the government’s proposal aims to keep, in 2027, the tax burden currently imposed through the IPI (the current federal tax on manufactured products) on the sectors that will become subject to the Excise Tax, including vehicles, vessels and aircraft, tobacco products, alcoholic and sugary drinks, mineral goods and betting.
Because of the postponement, the Excise Tax cannot be charged from January 1, 2027, due to the 90-day rule set out in Article 150, III, “c”, of the Federal Constitution. Therefore, if the provisional measure is published at the end of October, the tax may only be charged between the end of January and the beginning of February 2027, depending on the publication date.
Impact. The postponement keeps the 2027 rates undefined and requires attention from the affected sectors, especially regarding pricing, contract review and tax planning.
Deadline for the TCU to send the CBS rate calculation to the Senate ends on October 30
Articles 349 to 353 of Complementary Law No. 214/2025
As reported in our previous edition, on September 14 the Federal Revenue Service sent the Federal Court of Accounts (TCU) its proposal for calculating the CBS reference rate for 2027. Under the schedule set out in the legislation, the TCU has until October 30, 2026 to complete its review and send the calculations to the Federal Senate, which must set the rate by resolution by December 15, 2026.
As of the closing date of this edition, the rate had not yet been released. Its definition is especially important for companies’ tax planning, since 2027 will be the first year in which the CBS is effectively charged, replacing the PIS and the Cofins.
With the start of CBS collection approaching and the reference rate still undefined, discussions about a possible postponement of the tax reform have increased, especially considering the elections. While business associations and experts argue for extending the testing period to 2027, with a delay in the effective collection of the CBS, others consider it more likely that only specific adjustments will be made, without changing the schedule.
Since the transition schedule is set out in the Federal Constitution, any postponement would require a constitutional amendment, approved in two rounds of voting in both the Chamber of Deputies and the Federal Senate, by three-fifths of the members of each house. So far, no proposal with this specific purpose has been identified in Congress.
On the operational side, the press has reported that the government is considering easing some filing obligations in early 2027, by extending deadlines, temporarily waiving certain fields in tax documents and adopting a guidance period without fines. These measures, however, would not postpone the collection of the CBS.
Therefore, unless the law is changed, effective collection of the CBS is still scheduled to start on January 1, 2027, and companies should keep their adaptation schedules on track.
Impact. The definition of the CBS reference rate will allow companies to estimate more precisely the tax burden for 2027 and move forward with price projections, contract reviews and the configuration of their tax systems. Although there are discussions about a possible postponement of collection and the easing of filing obligations, the schedule set out in the legislation has not been formally changed. Companies should therefore keep planning for the effective collection of the CBS from January 1, 2027, while monitoring any changes to the transition rules and adaptation deadlines.
Payment by the buyer is expected to be automated as early as 2027
Complementary Law No. 214/2025 and statements by Serpro released in October 2026
Under the IBS and the CBS, the buyer’s right to take credits will, as a rule, depend on the payment of the taxes due on the purchase. In this context, Complementary Law No. 214/2025 provides for payment by the buyer (RAD), a mechanism that allows the buyer to pay the taxes on the transaction directly to the government and pay the supplier only the net amount of the purchase.
According to Robson Dias Lima, national manager of the tax reform project at Serpro (the federal data processing company), automated processing of the RAD will be available from January 2027, when effective collection of the CBS begins. Automation will also cover four other ways of settling taxes: offsetting with tax credits, partial or full payment through a tax payment form, and payment through split payment.
Under the legislation, if the amount paid by the buyer exceeds the outstanding tax due on the transaction, the difference must be transferred to the supplier within three business days from the payment date. However, not all features will be available in early 2027, as some still depend on regulations to be issued by the Federal Revenue Service and the IBS Management Committee (CGIBS).
Impact. Payment by the buyer may become an important option for companies seeking to secure their IBS and CBS credits, reducing their reliance on payment by the supplier, especially while split payment is being gradually implemented. The automation of the different payment methods will also require closer control over the reconciliation of tax documents, amounts paid and credits taken, making it necessary to adapt internal systems and procedures.
CBS already shown on 86% of tax documents issued by companies required to do so
Federal Revenue Service Consumption Transactions Register (ROC) dashboard, updated on October 8, 2026
The Federal Revenue Service released the first public data on how the CBS is being shown on electronic tax documents issued during the testing period of the tax reform. The information comes from the Consumption Transactions Register (ROC) dashboard, updated on October 8, and covers documents issued in the 30 days before October 7, 2026.
According to the data, about 86% of the invoices issued by companies required to do so showed the CBS, which corresponds to approximately 3.7 billion documents. Another 600 million were issued without it.
When looking at issuing establishments, however, the percentage is lower. Of the 1,275,356 establishments required to show the CBS that issued tax documents during the period, about 67% showed it on all or some of their transactions. Among the different types of documents, the highest compliance was found among issuers of CT-e (electronic transport documents) (87%), followed by issuers of NFCom (82%), NFC-e (81%) and NF-e (78%).
Impact. Although the data show progress in adapting invoicing systems, a significant share of establishments still does not fully comply with the new requirements. In 2026, the waiver of IBS and CBS payment depends on meeting the filing obligations, subject to the rules and correction procedures set out in the legislation. Companies should therefore review the configuration of their systems and fix any inconsistencies before 2027, when effective collection of the CBS begins, with effects on the calculation of taxes due and on the credits taken.
Deadline to join the Simplified National Tax Regime for 2027 has ended
CGSN Resolution No. 194/2026 and figures released by the Federal Revenue Service on October 16, 2026
The deadline, extended by CGSN Resolution No. 194/2026, for companies not yet in the Simplified National Tax Regime to request to join it for 2027 ended on October 15.
According to figures released by the Federal Revenue Service on October 16, 657,753 requests to join the regime were filed, of which 256,607 were approved and 401,146 were rejected. Companies whose requests were rejected may fix the issues preventing them from joining until October 30, 2026, so that they can join the regime from January 2027.
The figures also showed 917,331 requests to opt into the regular IBS and CBS regime, an option available to companies in the Simplified National Tax Regime that wish to pay these taxes outside the simplified regime. This option remains open until October 30, 2026, with effect for the first half of 2027, and it may be cancelled between November 3 and December 20, 2026.
Impact. The high number of rejections shows how important it is for companies wishing to join the Simplified National Tax Regime to check and fix any pending issues by October 30, or they will not be able to join for 2027. For companies already in the simplified regime, the approaching deadline to opt into the regular IBS and CBS regime requires an assessment of the effects on the tax burden, on the use and transfer of credits and on pricing, also taking into account their customer profile.
On the Radar
| DATE | MILESTONE |
|---|---|
| Oct 30, 2026 | Simplified National Tax Regime. Final deadline to fix pending issues in rejected requests to join the regime and to opt into the regular IBS and CBS regime for the first half of 2027. CBS rate. Deadline for the TCU to send its calculations to the Federal Senate. |
| Oct 31, 2026 | Cooperatives. Final deadline to register the option for the specific IBS and CBS regime, with effect in 2027, or to cancel the option already made. |
| Nov 3 to Dec 20, 2026 | Simplified National Tax Regime. Period to cancel the request to join the regime and the option for the regular IBS and CBS regime made for 2027. |
| Nov 16, 2026 | Split payment. Registration opens with the Federal Revenue Service and the CGIBS for other providers interested in the integration tests. |
| Dec 1, 2026 | NFS-e. IBS and CBS information becomes mandatory for services under items 1.03, 1.05, 1.09 and 16.01 of the ISS list, digital platforms, rentals, condominium fees and other supplies included in the December schedule. |
| Dec 15, 2026 | CBS rate. Deadline for the Federal Senate to set, by resolution, the reference rate that will apply in 2027. |
| Jan 1, 2027 | CBS. Start of effective collection. Simplified National Tax Regime. IBS and CBS information becomes mandatory in tax documents issued by companies in the regime, and the options for the Simplified National Tax Regime and for the regular IBS and CBS regime take effect. |
| Jan or Feb 2027 | Excise Tax. Possible start of collection, depending on the publication of the rule setting the rates and on compliance with the constitutional 90-day rule. |
This newsletter is a biweekly publication of the tax practice of SouzaOkawa Advogados and does not constitute legal advice on specific cases. The application of the rules discussed here depends on the analysis of the particular features of each transaction. Our team is available to clarify the impacts of the changes presented.
The content was produced by the SouzaOkawa Team. Use the Link above to access the (portuguese) PDF version