Counterfoil rule note
Quoted from a public specification. This page is not a validator, and it is not tax, legal, or accounting advice.
An Invoice that contains a VAT breakdown group (BG-23) with a VAT category code (BT-118) "Not subject to VAT" shall not contain other VAT breakdown groups (BG-23).
Source: https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/BR-O-11/
Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL
Severity note: fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.
If a VAT breakdown uses the category "Not subject to VAT", the invoice must not contain other VAT breakdown groups (BG-23). The official message says "other VAT breakdown groups" in the plural. It does not name a seller or buyer identifier, and it does not mention a VAT rate. The quoted category name has no space after the opening quote. The published test passes when no O VAT breakdown exists, because the negative branch is not(...) and does not call exists. When an O breakdown exists, the count of VAT tax categories whose code is not O must be 0. That count is a relative path, not a descendant search, and a second O category is not in it. The positive branch calls exists. The tax-scheme comparison is cbc:ID)='VAT' with no space before =. The O comparison is normalize-space(.) = 'O' with spaces around =. The other-category comparison is normalize-space(cbc:ID) != 'O' with spaces around !=.
When a VAT breakdown is category O, do not add another VAT breakdown group with a different category code.
Illustration of the condition in the official statement. Not an example published by the source.
Fails the stated condition. The invoice has an O VAT breakdown and another VAT breakdown whose category code is not O.
Passes the stated condition. The only VAT tax category is O, or the invoice has no O VAT breakdown.
Copied from the source. Not reimplemented on this page.
/ubl:Invoice | /cn:CreditNote
(exists(cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']/cbc:ID[normalize-space(.) = 'O']) and count(cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory[normalize-space(cbc:ID) != 'O'][cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']) = 0) or not(cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']/cbc:ID[normalize-space(.) = 'O'])
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