# BR-Z-04 Zero-rated document charge requires a seller VAT identifier

An invoice that contains a document level charge whose document level charge VAT category code (BT-102) is "Zero rated" shall contain the Seller VAT identifier (BT-31), the Seller tax registration identifier (BT-32) and/or the Seller tax representative VAT identifier (BT-63).

## Problem Description

An invoice that contains a document level charge whose document level charge VAT category code (BT-102) is "Zero rated" shall contain the Seller VAT identifier (BT-31), the Seller tax registration identifier (BT-32) and/or the Seller tax representative VAT identifier (BT-63).

> **ERROR**: XRechnung 3.0

## Context and Significance

This EN16931 rule mirrors BR-Z-02/BR-Z-03 for zero-rated (category Z) document level charges, keeping the seller identifiable.

## Solution

Provide the seller VAT identifier (BT-31), tax registration identifier (BT-32) or tax representative VAT identifier (BT-63) whenever a document level charge uses category Z.

- validate
- convert

## Valid Examples

- Document charge with category Z at 0 % and seller VAT identifier DE123456789 present

## Invalid Examples

- Document charge with category Z but no BT-31, BT-32 or BT-63 on the seller party

## Code Examples

### Valid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>true</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">15.00</cbc:Amount>
  <cac:TaxCategory><cbc:ID>Z</cbc:ID><cbc:Percent>0</cbc:Percent></cac:TaxCategory>
</cac:AllowanceCharge>
<!-- seller party carries cac:PartyTaxScheme/cbc:CompanyID DE123456789 (BT-31) -->
```

### Invalid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>true</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">15.00</cbc:Amount>
  <cac:TaxCategory><cbc:ID>Z</cbc:ID><cbc:Percent>0</cbc:Percent></cac:TaxCategory>
</cac:AllowanceCharge>
<!-- seller party has no BT-31, BT-32 or BT-63 -->
```

## Affected Fields

- [BT-31 Seller VAT identifier](/resources/xrechnung/bt-31-seller-vat-identifier)
- [BT-32 Seller tax registration identifier](/resources/xrechnung/bt-32-seller-tax-registration-identifier)
- [BT-63 Seller tax representative VAT identifier](/resources/xrechnung/bt-63-seller-tax-representative-vat-identifier)
- [BT-102 Document level charge VAT category code](/resources/xrechnung/bt-102-document-level-charge-vat-category-code)

## Related Rules

- [BR-Z-02](/resources/kosit-validator-errors/br-z-02-zero-rated-line-seller-vat-id)
- [BR-Z-03](/resources/kosit-validator-errors/br-z-03-zero-rated-allowance-seller-vat-id)
- [BR-Z-07](/resources/kosit-validator-errors/br-z-07-zero-rated-charge-rate-zero)

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.