SIMPLES NACIONAL AND THE TAX REFORM: WHAT COMPANIES NEED TO KNOW ABOUT THE NEW DEADLINES FOR 2027

A Tax Overhaul That Directly Affects Small Businesses

Brazil's tax environment is undergoing one of the most profound transformations in its history. The Tax Reform, approved through Constitutional Amendment No. 132/2023 and regulated by Complementary Law No. 214/2025, completely redesigns consumption taxation in the country. Amid this structural change, business owners and managers of microenterprises and small businesses face a concrete challenge: understanding how Simples Nacional (the simplified tax regime for micro and small businesses) and the new taxes — the Tax on Goods and Services (IBS) and the Social Contribution on Goods and Services (CBS) — will coexist during the transition period.

In April 2026, the Simples Nacional Management Committee (CGSN) published CGSN Resolution No. 186, establishing specific deadlines and conditions for opting into Simples Nacional for the 2027 calendar year and for joining the regular assessment regime for IBS and CBS. This is a rule with significant practical impact, unanimously approved at the CGSN's 70th in-person meeting, and it demands immediate attention from business owners. Understanding its implications can make the difference between a smooth transition and unnecessary tax costs.

The Context of the Reform: IBS, CBS and Simples Nacional

To understand the relevance of CGSN Resolution No. 186, it is necessary to place the issue within the context of the Tax Reform. The new model provides for the gradual replacement of five existing taxes — including PIS, Cofins, ICMS, and ISS — with two new ones: the IBS, under shared jurisdiction of states and municipalities, and the CBS, under federal jurisdiction. The transition will take place in stages between 2026 and 2032, a period during which the old and new taxes will coexist.

For companies opting into Simples Nacional, this process creates additional complexity. The simplified regime consolidates, into a single collection document, all taxes owed by the company, including, until now, the contributions that will be replaced by the IBS and the CBS. Starting in 2027, Simples Nacional will need to adapt to the new tax architecture, and companies will have to decide, in advance, how they want to assess and collect the new consumption taxes.

The Earlier Election Deadline: September 2026

One of the main innovations of CGSN Resolution No. 186 is moving up the election period for Simples Nacional for the 2027 calendar year. Unlike previous years, when the election is made in January, the rule establishes that the election must be formalized between September 1 and September 30, 2026, through the Simples Nacional Portal, taking effect as of January 1, 2027.

This earlier deadline is not arbitrary. It stems from the need to align the simplified regime's procedures with the implementation of the IBS and the CBS, which will be fully in effect starting in 2027. By knowing in advance which companies will be under Simples Nacional, public authorities can properly structure the assessment and collection systems for the new taxes, ensuring legal certainty throughout the process.

From a business standpoint, this earlier timeline represents a tax planning opportunity. In the months leading up to September 2026, managers will have enough time to analyze whether remaining in Simples Nacional is economically advantageous given the changes brought by the reform, considering factors such as the industry sector, the supplier chain, and the tax credit structure.

Electing the Regular IBS and CBS Regime: Flexibility During the Transition

CGSN Resolution No. 186 also introduces an important novelty: the possibility for companies enrolled in Simples Nacional to exceptionally elect the regular assessment and collection regime for the IBS and the CBS, applicable exclusively to the period from January to June 2027. This election must be made during the same period as the Simples Nacional election, that is, between September 1 and September 30, 2026.

Choosing the regular IBS and CBS regime does not exclude the taxpayer from Simples Nacional. In practice, the company will continue to pay all other taxes under the simplified regime, but the portions related to IBS and CBS will be assessed and collected according to the general rules of the new tax system. This optionality gives companies a period to adapt to and test the new regime without giving up the advantages of Simples Nacional for other taxes.

For certain segments, especially those operating in production chains where buyers are taxpayers under the regular regime, this option may be economically favorable. This is because, under the regular regime, the IBS and the CBS allow for the assessment of tax credits, which can make the company more competitive with its buyers. The decision, therefore, requires a careful analysis of the value chain and the specific characteristics of each business.

Cancellation of the Election and Deadline for Regularization

The rule preserves protective mechanisms for taxpayers in the event of changing circumstances. Both the election for Simples Nacional and the election for the regular IBS and CBS regime may be irrevocably canceled until the last day of November 2026. This deadline gives companies a review window of about two months after formalizing their election, during which changes in revenue, ownership structure, or market conditions may occur that justify reconsideration.

The resolution also provides that, in the event the Simples Nacional election is denied, the company will have up to 30 days to resolve the disqualifying issues, counted from notice of the denial. If the issues are resolved within this period, the denial will be canceled and the election will be approved. This provision prevents irregularities that can be quickly resolved — such as tax debts in the process of being installment-paid or settled — from permanently barring enrollment in the simplified regime.

This is a guideline aligned with the spirit of Complementary Law No. 123/2006, known as the National Statute for Microenterprises and Small Businesses, which establishes differentiated and favorable treatment for micro and small businesses as a constitutional principle set forth in Article 179 of the Federal Constitution.

Rules for Newly Established Companies

CGSN Resolution No. 186 establishes specific rules for companies formed between October 1 and December 31, 2026. For these companies, the exceptional September deadline system does not apply. The election made at the time of CNPJ (corporate taxpayer ID) registration for Simples Nacional will take effect as of the registration date and for the entire 2027 calendar year. The election for the regular IBS and CBS regime, in turn, will take effect for the months of January through June 2027.

This distinction ensures equal treatment between companies already in operation and those starting activities in the last quarter of 2026, avoiding regulatory gaps that could create legal uncertainty. For entrepreneurs planning to open new companies during this period, it is essential to understand these rules and properly guide the incorporation process.

It is worth noting that the resolution does not apply to the Fixed Monthly Amounts Collection System for Taxes Covered by Simples Nacional (SIMEI), intended for individual microentrepreneurs (MEI). For the MEI, the specific rules already set out in their own regulations remain in place, preserving the simplicity that characterizes this regime.

Practical Implications for Business Tax Planning

From a strategic standpoint, CGSN Resolution No. 186 places managers of small and medium-sized businesses in the position of having to make decisions based on concrete data about the reality of each business. The September 2026 deadline is not far off, and the time to begin proper analysis is now.

Among the relevant variables for this decision are: the company's revenue volume and how close it is to the Simples Nacional eligibility threshold, which is R$4.8 million per year; the profile of the company's customers, considering whether they are end consumers or taxpayers under the regular IBS and CBS regime; the nature of the inputs used in the business activity and the possibility of using tax credits under the regular regime; and the company's cost structure relative to the rates set out in the Simples Nacional tables for each business sector.

A combined analysis of these factors allows business owners to make the decision best suited to their company's reality, minimizing tax risks and maximizing tax efficiency under the new scenario.

Early Planning as a Competitive Advantage

The publication of CGSN Resolution No. 186 is a clear sign that the transition to Brazil's new tax system is moving forward at a concrete pace. For entrepreneurs and managers of microenterprises and small businesses, ignoring these changes could mean a loss of competitiveness, an increase in the effective tax burden, and, in more serious cases, tax irregularities resulting from improper regime classification.

The key to navigating this process safely lies in early planning. The September 2026 window may seem far away, but the tax analysis needed for a well-founded decision requires time, data, and specialized knowledge of the particularities of each sector and each company. Companies that begin this process early will be better positioned to explore the opportunities offered by the new system, such as the potential to use IBS and CBS tax credits under the regular regime.

In this context, specialized legal and tax advisory services play a fundamental role. The Tax Reform, while representing a necessary structural advance for Brazil, introduces a level of regulatory complexity that requires qualified technical interpretation. Decisions made without proper grounding can generate tax liabilities that compromise a business's financial health. Seeking professional guidance before the September 2026 deadline is, therefore, a matter of prudence and sound business judgment.