# BR-CO-26

> In order for the buyer to automatically identify a supplier, the Seller identifier (BT-29), the Seller legal registration identifier (BT-30) and/or the Seller VAT identifier (BT-31) shall be present.

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/br-co-26

## Official rule text

In order for the buyer to automatically identify a supplier, the Seller identifier (BT-29), the Seller legal registration identifier (BT-30) and/or the Seller VAT identifier (BT-31) shall be present.

## Why did my invoice fail BR-CO-26?

So the buyer can automatically identify the supplier, at least one of the Seller identifier (BT-29), Seller legal registration identifier (BT-30) or Seller VAT identifier (BT-31) must be present. An invoice with only a seller name/address gives no reliable key to match the supplier in the buyer's systems.

## Common causes

- AccountingSupplierParty has a name and address but no PartyIdentification/ID (BT-29), no PartyLegalEntity/CompanyID (BT-30), and no PartyTaxScheme VAT ID (BT-31).
- Seller is a non-VAT-registered small business and no legal registration ID or scheme identifier was added as a substitute.
- VAT ID stored under a non-VAT TaxScheme (e.g. tax registration) so it is not recognised as BT-31.
- Identifier fields present in the source data but not mapped into the UBL party elements.

## How do I fix it?

```
Add at least one seller identifier, e.g. the VAT ID: <cac:PartyTaxScheme><cbc:CompanyID>SI12345678</cbc:CompanyID><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:PartyTaxScheme>, or a legal registration ID via <cac:PartyLegalEntity><cbc:CompanyID schemeID="0199">...</cbc:CompanyID></cac:PartyLegalEntity>.
```