Executive summary

On 18 June 2026, the Brazilian Federal Revenue Service (RFB) published Normative Instruction (NI) No. 2,329/2026, introducing amendments to the Additional Social Contribution on Net Profit (CSLL) regulations. In Brazil, the Additional CSLL — regulated by NI No. 2,228/2024 — introduced a Qualified Domestic Minimum Top-up Tax (QDMTT) aligned with the Organisation for Economic Co-Operation and Development (OECD) Pillar Two Global Anti-Base Erosion (GloBE) rules. (For background, see EY Global Tax Alert, Brazilian Government publishes Provisional Measure introducing OECD Pillar Two rules, dated 4 October 2024.)

The amendments focus primarily on procedural and compliance matters, including the exercise of elections, fiscal-year alignment, centralized payment mechanisms and reporting obligations for multinational enterprise (MNE) groups.

Key changes introduced by NI No. 2,329/2026

Formalization of the Designated Constituent Entity election through payment

Under NI No. 2,228/2024, MNE groups may elect to assign liability for the Additional CSLL to a Designated Constituent Entity, which will act as both the taxpayer and the party responsible for compliance purposes. NI No. 2,329/2026 clarifies that this election is formalized through the payment of the Additional CSLL, with the appropriate identification of the designated entity responsible for the centralized payment. This clarification establishes that the election is made through the payment process itself, providing a practical mechanism for formalizing the designation.

Addressing fiscal-year mismatches

NI No. 2,329/2026 introduces Article 128-A to NI No. 2,228/2024, addressing situations in which the fiscal year of the group's Country-by-Country Reporting (CbCR) differs from the Brazilian jurisdictional fiscal year. The Country-by Country (CbC) report is the primary source of information for purposes of the Transitional CbCR Safe Harbour (TCSH), which may reduce the Additional CSLL to zero for fiscal years beginning before 31 December 2026, if certain conditions are met.

Under the new provision, MNE groups may choose to use information from either:

• The CbC report of the fiscal year ending within the Brazilian jurisdictional fiscal year
• The CbC report of the fiscal year beginning within the Brazilian jurisdictional fiscal year

The rule also establishes that the election is irrevocable and must be applied consistently across all relevant fiscal years.

This clarification is welcome because Brazilian Constituent Entities commonly use a calendar year for local reporting purposes, while the broader MNE group may adopt a different fiscal year. Because the Additional CSLL follows the Brazilian fiscal year, uncertainty existed regarding which CbC report should be used for TCSH purposes. The new rule provides operational flexibility, although the irrevocable nature of the election warrants careful consideration.

Additional CSLL information reporting

Regarding the Additional CSLL reporting, NI No. 2,329/2026 confirms that the information necessary for the calculation of the Additional CSLL, including the elections made, will need to be provided within a separate ancillary obligation to be introduced by an additional normative act. This indicates that additional compliance obligations are forthcoming as Brazil continues to develop its QDMTT reporting framework.

Implications and next steps

NI No. 2,329/2026 further develops the operational framework for Brazil's QDMTT regime by clarifying election procedures, addressing fiscal-year mismatches and confirming additional reporting requirements.

MNE groups within scope should consider the following actions, depending on their particular circumstances:

• Evaluate the implications of the Article 128-A election and model the impact of each alternative on the TCSH tests.
• Establish internal procedures for formalizing any Designated Constituent Entity election through the payment process.
• Monitor future guidance regarding the new ancillary reporting obligation and prepare for additional compliance requirements.

Because the Article 128-A election is irrevocable and may affect TCSH outcomes under the De Minimis, Simplified Effective Tax Rate and Routine Profits tests, taxpayers should carefully assess the consequences of each alternative before making an election.