# BR-AE-06 Reverse charge document allowance VAT rate must be zero

In a document level allowance (BG-20) where the document level allowance VAT category code (BT-95) is "Reverse charge" (AE), the document level allowance VAT rate (BT-96) shall be 0 (zero).

## Problem Description

> **ERROR**: EN 16931 VAT category rule

## Context and Significance

Reverse charge amounts carry no seller-charged VAT, so every AE element — lines, allowances and charges — must use a zero rate for a consistent BG-23 breakdown. In practice, the error occurs when a volume or lump-sum discount keeps the standard rate although it reduces reverse charge lines.

## Solution

Set the reverse charge allowance cac:TaxCategory/cbc:Percent (BT-96) to 0 so it aligns with the zero-rated AE line rates.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-AE-06)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-AE-06)

## Valid Examples

- AE document allowance with BT-95 = AE and BT-96 = 0

## Invalid Examples

- AE document allowance with BT-95 = AE but BT-96 = 19

## Code Examples

### Valid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>false</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">50.00</cbc:Amount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
    <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
  </cac:TaxCategory>
</cac:AllowanceCharge>
```

### Invalid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>false</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">50.00</cbc:Amount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>19</cbc:Percent>
    <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
  </cac:TaxCategory>
</cac:AllowanceCharge>
```

## Affected Fields

- [BT-95 Document level allowance VAT category code](/resources/xrechnung/bt-95-document-level-allowance-vat-category-code)
- [BT-96 Document level allowance VAT rate](/resources/xrechnung/bt-96-document-level-allowance-vat-rate)

## Related Rules

- [BR-AE-05](/resources/kosit-validator-errors/br-ae-05-reverse-charge-line-rate-zero)
- [BR-AE-07](/resources/kosit-validator-errors/br-ae-07-reverse-charge-charge-rate-zero)
- [BR-AE-03](/resources/kosit-validator-errors/br-ae-03-reverse-charge-allowance-seller-buyer-vat-id)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.