The law puts the task in the hands of whoever settles the payment: electronic payment service providers and payment system operators separate IBS and CBS and pay them to CGIBS and the Federal Revenue Service (RFB) when the transaction for goods or services is financially settled (Source: LC 214/2025, art. 31).
In the vocabulary of the CBS regulation, to segregate means to reserve the amount of tax that will be paid (Source: Decree 12,955/2026, art. 28, § 1). In other words, the bank or payment institution separates the tax from the amount that would go to the supplier, and the supplier receives the rest.
Three ideas prevent most misunderstandings. First: split payment changes the timing and the channel of payment, not the tax assessment. The taxpayer remains responsible for any balance due, subject to the taxable event and the due date (Source: LC 214/2025, art. 34, IV).
Second: without a link between the tax document and the payment transaction, the mechanism cannot know how much to segregate, and Technical Note 2026.006 treats this link as strictly necessary to determine the supplier's debits and grant credit to the buyer (Source: NF-e Portal, NT 2026.006).
Third: the payment institution carries out the segregation, but it is not liable for the tax and does not validate what it receives. A data error starts on the side of whoever issues the document and starts the payment (Source: Decree 12,955/2026, art. 35).
Two other sections of the site cover the topic from a narrower angle. The ancillary obligations section describes the article of the law and how it fits with the bookkeeping.
The Split payment in testing section, on the reform page, offers four checks for the 2026 window. This page covers the whole mechanism, from document to transfer, with the effect on cash, on accounts receivable and payable, on banks and on what the ERP must record and reconcile.