# BR-AE-04 Reverse charge document charge needs seller and buyer VAT identifiers

An invoice with a document level charge (BG-21) whose VAT category code (BT-102) is "Reverse charge" (AE) 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), and the Buyer VAT identifier (BT-48) and/or the Buyer legal registration identifier (BT-47).

## Problem Description

An invoice with a document level charge (BG-21) whose VAT category code (BT-102) is "Reverse charge" (AE) 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), and the Buyer VAT identifier (BT-48) and/or the Buyer legal registration identifier (BT-47).

> **ERROR**: XRechnung 3.0

## Context and Significance

This mirrors BR-AE-03 for document level charges: reverse charge shifts VAT to the buyer, so both parties must be tax-identified when a charge carries category AE.

## Solution

Populate a seller tax identifier (BT-31, BT-32 or BT-63) and a buyer identifier (BT-48 or BT-47) on the invoice carrying the reverse charge charge.

- validate
- convert

## Valid Examples

- AE charge with seller BT-31 = DE123456789 and buyer BT-48 = FR32123456789

## Invalid Examples

- AE charge where the buyer VAT ID is present but no seller VAT ID (BT-31/BT-32/BT-63) is given

## Code Examples

### Valid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>true</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">30.00</cbc:Amount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
  </cac:TaxCategory>
</cac:AllowanceCharge>
<!-- with seller BT-31 and buyer BT-48 present on the parties -->
```

### Invalid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>true</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">30.00</cbc:Amount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
  </cac:TaxCategory>
</cac:AllowanceCharge>
<!-- buyer BT-48/BT-47 missing from AccountingCustomerParty -->
```

## 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-48 Buyer VAT identifier](/resources/xrechnung/bt-48-buyer-vat-identifier)

## Related Rules

- [BR-AE-01](/resources/kosit-validator-errors/br-ae-01-reverse-charge-vat-breakdown-required)
- [BR-AE-03](/resources/kosit-validator-errors/br-ae-03-reverse-charge-allowance-seller-buyer-vat-id)
- [BR-AE-02](/resources/kosit-validator-errors/br-ae-02-reverse-charge-seller-vat-id-required)

## 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.