Hybrid Simples Nacional: the Deadline Closes September 30 — Technical Checklist for Tax, Accounting, and IT Teams Before Midnight

The September window is closing: what the numbers already show

The deadline for companies under Simples Nacional to opt into the so-called hybrid IBS and CBS regime — collecting these two taxes outside the single DAS payment slip, under the regular regime — ends this Wednesday, September 30, 2026. The window, set forth by CGSN Resolution No. 186, of April 9, 2026, published in the Federal Official Gazette on April 17, established deadlines for micro and small businesses to exercise, between September 1 and 30, 2026, the option for Simples Nacional and the option to assess IBS and CBS under the regular regime for these taxes, with effects on the 2027 calendar year.

Data released this week by the Federal Revenue Service gives a sense of the scale of this movement: there are already 447,716 requests for the regular IBS and CBS regime within Simples Nacional, with the option deadline ending on September 30, 2026. At the same time, 213,451 Simples Nacional enrollment requests were denied by the tax administration, leaving taxpayers 30 days to resolve the tax and registration issues flagged by the system. This second figure matters especially for tax teams: unresolved registration issues now could jeopardize their classification in 2027.

How the hybrid regime works in practice

The Hybrid Simples Nacional is the option, established under the Tax Reform, to assess IBS and CBS separately from the DAS, while keeping other taxes under the single payment slip, allowing the generation of tax credits for the customers of the electing company. Operationally, this means that the company continues issuing the DAS for payroll and income taxes, but starts issuing separate payment slips and itemizing IBS and CBS on the invoice like a regular company.

From an accounting standpoint, by opting for the Hybrid Simples Nacional, the company must itemize IBS and CBS on its invoices, an itemization that enables the purchasing customer to claim the full credit — a key difference from the traditional Simples regime.

Who should evaluate the migration — and who probably doesn't need to

The decision is not one-size-fits-all. The model tends to make sense for companies that sell mostly to other legal entities under the regular regime, since, by itemizing IBS and CBS separately on the invoice, the business customer can claim the full credit for these amounts. For operations concentrated on end consumers, the math changes: the hybrid regime tends to be worthwhile for B2B businesses, with a high volume of taxed inputs or items with a 60% to 100% reduced tax rate, while those selling to end consumers or with costs concentrated in payroll are generally better off staying in the traditional Simples regime.

It's worth reinforcing a point that generates recurring doubts among tax teams: if no action is taken by the deadline, the company will automatically remain under the traditional regime, with all taxes unified under the DAS payment slip — opting into the hybrid regime is optional, and missing the window does not result in any exclusion from Simples Nacional.

What to check before midnight today

• Registration and tax compliance: review pending debts, since denials due to registration issues consume part of the resolution deadline.
• Customer profile: map the percentage of revenue coming from legal entities under the regular regime that actually claim credit.
• ERP configuration: invoicing systems need to be ready to itemize IBS/CBS separately on invoices and assess debit and credit item by item, should the option be chosen.
• Tax-financial integration: reconcile assessment outside the DAS with cash flow and control of accumulated credits, avoiding manual rework.

Reversibility and upcoming windows

Those who opt in now are not locked in until 2033. If the company changes its mind, the option made in September can be canceled until November 30, 2026, and there will be a new window to change the payment method in March 2027, with the change taking effect for the second half of that year. This semiannual cadence — September and March each year — should become part of the recurring agenda for tax and accounting teams, not just an isolated event this month.

This content is for informational purposes only and does not replace guidance from your accounting firm, which should assess the most appropriate classification considering the specific profile of the operation. If your company is evaluating the integration between ERP, invoicing, and IBS/CBS assessment for the hybrid or traditional regime, talk to Edoo.