NT 2026.004 RTC: what changes in NF3-e with IBS and CBS (and the deadline that tax and IT teams can't miss)

Another electronic tax document enters the Tax Reform radar: the NF3-e

While the market's attention is focused on NF-e, NFC-e, and NFS-e, the Federal Revenue Service published an important update for those working in the electric power sector: Technical Note 2026.004 – Consumption Tax Reform, which adjusts the layout and validation rules of the NF3-e, the Electronic Electric Energy Invoice. (cite index="28-1">The technical note updates the layout and validation rules of the Electronic Electric Energy Invoice (NF3-e) due to the implementation of the IBS and the CBS. For tax and IT teams at distributors, generators, traders, and large energy consumers who deal with this document, it's worth understanding what changes and when.

Confirmed dates: what takes effect and when

(cite index="28-5">The document, version 1.00, was published on October 1, 2026, and establishes changes to NF3-e fields, to the composition of the tax document's values, and to the validation rules. The implementation schedule has two milestones that can already be added to the calendar:

• (cite index="28-6">The changes related to the new fields and validation rules go into production on November 16, 2026.
• (cite index="28-7">The discontinuation of the regular NF3-e with adjustment is scheduled for December 14, 2026.

In other words: those who still use the NF3-e model with a separate adjustment document need to plan the process migration before the turn of December, under penalty of being left without an equivalent instrument in production.

Why the technical note creates net value fields

(cite index="28-8">According to the technical note, the change seeks to increase transparency about price formation and allow separate identification of the net value of the service and the taxes embedded in the price. This follows the same logic already seen in other 2026 Technical Notes (such as NT 2026.008, on net product value, for NF-e and NFC-e): the tax authority wants the tax document to show separately how much is actually the service provision and how much are the taxes that make up the final price.

One point that frequently raises doubts among tax teams is whether the IBS and CBS start to be included in their own calculation base within the new field. (cite index="28-9,28-10">The change does not mean that the taxes will start to be included in their own calculation bases — according to the NT, IBS and CBS are calculated on top and the amounts highlighted in the respective tax groups will already be included in the service value. It's worth carefully checking this rule when reconciling the total invoiced amount with the XML's tax groups.

Other changes brought by NT 2026.004

In addition to the net value fields, the document brings relevant operational adjustments for those who develop or certify NF3-e issuing systems:

• (cite index="28-11">Creation of an exception in the rate validation rules in the testing environment, allowing tests with 2027 rates.
• Change to the rule for composing the tax document's total value.
• Inclusion of IBS and CBS fields in the relevant NF3-e groups.

The possibility of testing 2027 rates in the testing environment already today is a sign that the calibration schedule for next year is being prepared in advance — something worth monitoring closely, since the CBS reference rate for 2027 is still being processed among the Federal Revenue Service, the TCU, and the Senate.

What tax and IT teams should check now

• Map whether the company or client served issues NF3-e (distributors, generators, energy traders, and qualifying self-producers).
• Check with the issuing system provider whether the update to the version compatible with NT 2026.004 is already scheduled before November 16, 2026.
• Identify internal processes that still depend on the Adjustment NF3-e and plan the transition before December 14, 2026.
• Review tax and accounting reconciliation routines that use the document's total value, since the composition of this value changes.
• Test in the certification environment, including simulating 2027 rates, to avoid surprises when the final calibration arrives.

This content is for informational purposes only and does not replace guidance from your accounting or tax advisory firm, which should assess the specific impact of each rule on your business.

If your company needs to keep tax systems up to date with the fast pace of Tax Reform Technical Notes, talk to Edoo.