PEPPOL-EN16931-P0105: Keep the not subject to VAT code VATEX-EU-O for category O breakdowns

The short answer

PEPPOL-EN16931-P0105 fails for each cac:TaxCategory that carries VATEX-EU-O while its cbc:ID is not O. The code states that the supply is not subject to VAT at all, which is what category O means; next to any other category it contradicts the treatment that category declares.

The recorded example is a reverse-charge invoice to a buyer with a German VAT identifier: category AE, reason text Reverse charge, and VATEX-EU-O as well. A cross-border service can look outside the scope from the seller side, but when the customer accounts for the VAT the treatment is the reverse charge, whose code is VATEX-EU-AE.

What the rule checks

The rule matches a cac:TaxCategory on its exemption code after upper-casing, so mixed case is no way round it: Vatex-EU-o in the reverse-charge breakdown was reported when tried. The category must then be exactly O once trimmed.

It fails whatever the other category is. When tried, VATEX-EU-O in an export breakdown, category G, was reported by this rule alone, as it was in the recorded AE breakdown.

Replacing the code settles the recorded case: with VATEX-EU-AE in place of VATEX-EU-O, the reverse-charge invoice passed every layer when tried.

Moving the category is the heavier change. When tried, relabelling the breakdown and the line of the recorded example as O cleared this rule but brought BR-O-02, because a document with an O line may carry no VAT identifiers, and BR-O-05, because an O line may carry no rate.

How an integration ends up here

Possible causes, from the shape of the rule rather than from measured usage:

• Cross-border business services are set up as outside the scope in the seller system, because the place of supply is abroad, while the invoice category follows the reverse-charge rules.
• A default exemption code of VATEX-EU-O is written into every breakdown with no VAT.
• The category is chosen from the customer type and the exemption code from the product, and the two settings were never lined up.

How to fix it

1. Decide which treatment applies. O is for supplies outside the scope of VAT altogether; if the customer accounts for the VAT under the reverse charge, the treatment is AE.
2. For a reverse-charge supply, keep AE and give VATEX-EU-AE, reason text, or both, as BR-AE-10 requires. The corrected example keeps the text Reverse charge and drops the code.
3. For a supply that really is not subject to VAT, change the breakdown and every line it covers to O and keep VATEX-EU-O. Remove the line VAT rates, which BR-O-05 forbids, and the seller and buyer VAT identifiers, which BR-O-02 forbids.

Validate your corrected invoice

Before and after

These are fragments, not complete documents. The complete synthetic documents they come from are linked below.

Fragment of the failing invoice: a reverse-charge breakdown carrying the not subject to VAT code

<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="GBP">25.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="GBP">0.00</cbc:TaxAmount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
    <cbc:TaxExemptionReasonCode>VATEX-EU-O</cbc:TaxExemptionReasonCode>
    <cbc:TaxExemptionReason>Reverse charge</cbc:TaxExemptionReason>
    <cac:TaxScheme>
      <cbc:ID>VAT</cbc:ID>
    </cac:TaxScheme>
  </cac:TaxCategory>
</cac:TaxSubtotal>

Fragment of the corrected invoice: the reverse-charge breakdown states its reason as text

<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="GBP">25.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="GBP">0.00</cbc:TaxAmount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
    <cbc:TaxExemptionReason>Reverse charge</cbc:TaxExemptionReason>
    <cac:TaxScheme>
      <cbc:ID>VAT</cbc:ID>
    </cac:TaxScheme>
  </cac:TaxCategory>
</cac:TaxSubtotal>

The failing invoice adds <cbc:TaxExemptionReasonCode>VATEX-EU-O</cbc:TaxExemptionReasonCode> to its reverse-charge breakdown; the corrected one keeps category AE with the text Reverse charge alone. Only this Peppol rule is reported: the text satisfies BR-AE-10, and VATEX-EU-O is a listed code for BR-CL-22.

Where it applies

• Applies to UBL Invoice and CreditNote. When tried, an exempt credit note with VATEX-EU-O reported this rule.
• Reported on the Peppol layer only. The EN 16931 rule for category O breakdowns, BR-O-10, asks for some reason there but does not look at codes placed in other categories.
• The code is read in the VAT breakdown and in document-level allowances and charges. Line categories are cac:ClassifiedTaxCategory elements and lie outside the rule.

Related rules

• BR-O-10 requires a reason, such as VATEX-EU-O, on a breakdown that really is category O
• BR-AE-10 requires the reverse-charge reason that the corrected breakdown gives as text
• PEPPOL-EN16931-P0107 ties the reverse-charge code VATEX-EU-AE to category AE
• BR-O-02 forbids VAT identifiers on a document with a not subject to VAT line
• Browse every rule in the reference
• Background: How Peppol invoice validation actually works

Scope and source

Written for Peppol BIS Billing 3.0.21 (May 2026), EN 16931 1.3.16, as applied to UBL 2.1 Invoice and CreditNote documents. Other profiles, syntaxes and releases can define this identifier differently. Guidance version 2026-09-28.1: source checked 2026-09-28, explanation last updated 2026-09-28.

The official definition of PEPPOL-EN16931-P0105 carries the normative wording and test. This page is our explanation of it, not a copy.

Guidance does not change the engine verdict. Fixing this finding does not mean the document passes every layer, and validation does not certify legal or tax compliance or transmit a document over Peppol.