CBS reference rate enters dispute in the Senate
The week brought a major twist to the Tax Reform timeline. After the Federal Audit Court (TCU) approved, on October 28, the CBS reference rate at 11.3468% (rounded to 11.3%) for 2027, the reaction in the Senate was one of open distrust. In the Economic Affairs Committee (CAE), Senator Eduardo Braga (MDB-AM), appointed rapporteur of the matter by the committee's chairman, Renan Calheiros, stated that the percentage caught everyone by surprise. (cite index="35-4,35-5">That wasn't the forecast set by the Federal Revenue Service's own studies or by the studies commissioned at the time from the Federal Audit Court. Therefore, all of us were caught by surprise by a rate of 11.3%, Braga said during the session. According to him, the previous expectation ranged between 8% and 9%, well below the TCU's final number.
Public hearing scheduled for November 10
At the same meeting on November 3, the CAE unanimously approved request REQ 107/2026, submitted by Senator Izalci Lucas (PL-DF), to hold a public hearing on the calculation criteria and economic impacts of the rate. (cite index="40-5">The debate is scheduled to take place on that very Tuesday (11/10/2026), during a committee meeting. The hearing is expected to bring together representatives from the TCU, the Federal Revenue Service, the Ministry of Finance, state finance secretariats, and entities from the productive sectors, including the National Confederation of Industry. Coincidentally, November 10 is also the date by which (cite index="34-1">the Federal Audit Court must send to the Senate Presidency the study that set the reference rate for the Contribution on Goods and Services at 11.3% for 2027, a document that will support the Senate Resolution Bill (PRS 50/2026) responsible for setting the definitive percentage.
Izalci Lucas went further: (cite index="40-6">he reported that he had sent a letter to the Senate Board requesting clarification on the legislative procedure for approving the resolution that will set the rate, in addition to demanding that the Finance Ministry provide the complete data used in the calculation. Senator Esperidião Amin, in turn, raised a point that worries the productive sector: the future sum of CBS and IBS could exceed 30%, although Braga argued for focusing the initial debate solely on CBS, since the IBS rate has not yet been defined.
What happens if the Senate doesn't decide in time
The legal timeline remains tight: (cite index="36-8">the Senate has until December 15 to set the reference rate through a resolution. If this resolution is not voted on within the deadline, (cite index="47-7">the percentage calculated by the TCU will prevail, with an additional margin reported by other sources until December 22. In practice, this means that companies, accounting firms, and IT teams structuring billing for 2027 could spend the coming weeks without knowing which number to use in their pricing and tax simulation systems.
27 entities request postponement of effective collection to 2028
Alongside the Senate discussion, a mobilization from the legal and tax sector has gained momentum. In an open letter released on October 31, (cite index="24-3">27 organizations argue that the lack of regulatory definitions and operational difficulties are jeopardizing taxpayers' preparation for the new stages of the consumption tax reform, scheduled for January 1, 2027. Among the signatories are entities such as the OABRJ, the Brazilian Institute of Lawyers (IAB), and the São Paulo Association of Tax Studies (APET).
The document proposes that (cite index="20-1">the effective implementation of the Contribution on Goods and Services be postponed to at least 2028, with 2027 reserved for conducting tests. One of the central arguments is the tight timeline for the tax definition: (cite index="27-4">the rate is expected to be announced on December 15, 2026, leaving taxpayers just over two weeks to assess the economic impacts of the new taxation. The letter also points out that (cite index="25-8">the assisted assessment system for IBS and CBS is not yet fully operational, which compromises integration testing between ERPs, fiscal issuers, and the systems of the Revenue Service and the IBS Management Committee.
It's worth noting: (cite index="23-7">so far, the official timeline has not been changed, but the entities' mobilization signals real concerns about the operational feasibility of the change. In other words, nothing changes in practice yet — but the risk of a timeline change is no longer hypothetical.
Why this matters for those handling tax and IT
For tax, accounting, and IT teams, the message is clear: keep preparing for CBS to take effect in January 2027, but closely monitor the Senate resolution and any potential legislative repercussions from the letter signed by the 27 entities. Three practical points deserve attention in the coming weeks:
- Follow the public hearing on 11/10 at the CAE, which may indicate whether the Senate will maintain, reduce, or reopen the discussion on the 11.3%;
- Keep pricing simulation systems flexible enough to quickly recalculate scenarios with different rates, since the definition is only expected around 12/15;
- Watch for any schedule changes to the IBS/CBS assisted assessment system, mentioned in the entities' letter as not yet fully operational.
This content is for informational purposes only and does not replace guidance from your accounting team, which should assess the specific impact of the CBS reference rate on your company's operations.
Edoo closely monitors every update to the Tax Reform fiscal calendar to keep your operation up to date within Odoo. Talk to Edoo and find out how to prepare your company for the upcoming rate definitions.
CBS at 11.3%: Senate questions TCU's calculation, calls public hearing for 11/10 and entities request postponement of collection to 2028