Simples Decision 2027.
Stay or opt in?

The single window of September 2026

Complementary Law 214/2025 and CGSN Resolution 186/2026 (published April 17, 2026) set a 30-day window — between September 1 and 30, 2026 — for Simples Nacional companies to decide their 2027 IBS/CBS regime.

It is a unique decision in Brazilian tax history: no tax-regime decision has had such a short window with such broad effects. The option for the regular regime takes effect on January 1, 2027 and is valid for the first half of 2027 — and it can be cancelled, irretractably, until the end of November 2026.

Path A — Stay in Simples Nacional

It keeps the unified payment in the DAS (Simples Nacional Collection Document), with an aggregate rate ranging from 4% to 33% depending on the activity annex and revenue bracket. Operationally it stays simple — a single monthly slip, a single assessment, with no need to adapt the ERP for IBS/CBS.

The commercial point: the B2B customer gets a reduced IBS/CBS credit

When a customer buys from a Simples supplier that stayed in the unified DAS, the customer still takes an IBS/CBS credit — but a reduced one, limited to the fraction effectively paid within the DAS, not the full rate. It is a smaller credit, not a zero credit. (The full rate is not yet set in law — 26.5% is a trigger ceiling, not the rate in force — art. 475.)

Practical result: the same good or service generates a larger credit when bought from a regular-regime supplier than from a Simples one — the difference is the magnitude of the credit (a reduced fraction of the DAS vs the full rate), not its existence. In a business purchasing decision, that differential can be decisive.

Who this path makes sense for

• Companies with an individual end customer (B2C) — an individual consumer does not take an IBS/CBS credit, so there is no competitive loss
• Retail direct to the consumer — physical stores, B2C e-commerce
• Service providers to individuals — clinics, salons, private schools for individuals
• Companies with residual B2B volume (<20% of revenue) — limited potential loss

Path B — Opt into the regular IBS/CBS regime

The company stays in Simples for the other taxes (IRPJ, CSLL, employer social security, and other federal taxes), but begins to assess IBS and CBS separately — breaking out the credit on the invoice at the full rate (not yet set in law; 26.5% is a trigger ceiling, art. 475). The B2B customer takes the full credit, preserving commercial competitiveness.

The operational costs of Path B

The company gains two new obligations:

1. Monthly assessment of IBS and CBS — separate from the Simples assessment, with its own bookkeeping
2. Collection via a DARF separate from the DAS — two monthly slips instead of one

In addition, there is an initial adaptation cost: the ERP must be configured to issue NF-e under the Reform (NT 2025.002) with IBS/CBS fields, the tax team must be trained in the new rules, and accounting processes must be reviewed.

Who this path makes sense for

• B2B companies selling to Actual Profit — the customer is sensitive to credit; significant potential loss if you stay in Simples
• Industries with long chains — the intermediary customer needs the credit to pass it on
• Technical service providers to large companies — supplier approval may require a CNPJ under the regular regime
• Companies with a majority B2B (>60% of revenue) — the risk of customer migration is too high to stay

Decision matrix by profile

Recommended quantitative modeling

Before deciding, it is advisable to model two scenarios for the next 12 months (Jan-Dec 2027):

1. Stay scenario: current revenue × probability of retaining each B2B customer given the reduced credit (versus a regular-regime supplier) = projected revenue
2. Migrate scenario: current revenue × additional operating cost of separate IBS/CBS assessment + ERP/tax adaptation cost = projected net margin

In mid-market B2B companies with revenue above BRL 1M/month, the difference between scenarios is usually 20-40% of the annual operating margin — figures that are relevant for a strategic decision.

Risks of the wrong decision

The cost of a wrong decision in the Simples Decision 2027 is asymmetric:

• Staying wrong (should have migrated): the loss of B2B competitiveness costs revenue over the period — customers migrate to suppliers in the regular regime (the magnitude varies by customer base)
• Migrating wrong (should have stayed): adds only operating cost (separate assessment, separate collection) without necessarily affecting revenue

In industrial supply chains and in the provision of technical services to large companies, we observe a strong tendency for the buyer to require a CNPJ under the regular regime as a prerequisite for contracting from 2027. Simples companies that do not migrate may be summarily excluded from supplier-approval processes, especially in segments where the tax credit is a material part of the purchasing decision.

What NOT to do

1. Do not wait until September 2026 to start the analysis — modeling takes 30-60 days if done correctly
2. Do not decide with accounting alone — the decision is strategic-commercial, not just tax
3. Do not copy a similar company’s decision — each customer base has a unique composition