# BR-CO-09

> The Seller VAT identifier (BT-31), the Seller tax representative VAT identifier (BT-63) and the Buyer VAT identifier (BT-48) shall have a prefix in accordance with ISO code ISO 3166-1 alpha-2 by which the country of issue may be identified. Nevertheless, Greece may use the prefix ‘EL’.

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/br-co-09

## Official rule text

The Seller VAT identifier (BT-31), the Seller tax representative VAT identifier (BT-63) and the Buyer VAT identifier (BT-48) shall have a prefix in accordance with ISO code ISO 3166-1 alpha-2 by which the country of issue may be identified. Nevertheless, Greece may use the prefix ‘EL’.

## Why did my invoice fail BR-CO-09?

The Seller VAT identifier (BT-31), Seller tax representative VAT identifier (BT-63) and Buyer VAT identifier (BT-48) must each begin with a two-letter ISO 3166-1 alpha-2 country prefix so the issuing country is identifiable, with Greece allowed to use "EL" instead of "GR". This standardizes VAT numbers for cross-border validation.

## Common causes

- VAT number stored without the country prefix (e.g. "12345678" instead of "DE12345678").
- Using the numeric-only national tax number rather than the EU VAT identifier.
- Greek VAT numbers prefixed with "GR" where the rule (and VIES) expects "EL" — note Peppol/EN allows EL.
- Lowercase or malformed prefix, or a non-ISO country code.

## How do I fix it?

```
Prefix the VAT id with the ISO country code on the correct scheme: <cac:PartyTaxScheme><cbc:CompanyID>DE123456789</cbc:CompanyID><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:PartyTaxScheme> (use EL... for Greece).
```