# UBL-SR-12

> Seller VAT identifier shall occur maximum once

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-12

## Official rule text

Seller VAT identifier shall occur maximum once

## Why did my invoice fail UBL-SR-12?

The Seller VAT identifier (BT-31), the seller's value added tax identifier, may occur at most once. In UBL it is the cac:AccountingSupplierParty/cac:Party/cac:PartyTaxScheme entry whose cac:TaxScheme/cbc:ID is 'VAT', and only one VAT-scheme entry is permitted for the seller.

## Common causes

- The seller is registered for VAT in several countries and each is emitted as a PartyTaxScheme with TaxScheme ID 'VAT'.
- A VAT number is duplicated across two cac:PartyTaxScheme blocks.
- The tax representative's VAT ID is mistakenly added under the seller party with scheme 'VAT'.

## How do I fix it?

```
Keep a single VAT entry: <cac:PartyTaxScheme><cbc:CompanyID>DE123456789</cbc:CompanyID><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:PartyTaxScheme>; put any non-VAT registration under a separate scheme (e.g. 'TAX').
```