# BR-AE-09 Reverse charge VAT category tax amount must be zero

The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where the VAT category code (BT-118) is "Reverse charge" (AE) shall be 0 (zero).

## Problem Description

The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where the VAT category code (BT-118) is "Reverse charge" (AE) shall be 0 (zero).

> **ERROR**: XRechnung 3.0

## Context and Significance

Reverse charge leaves the seller with no output VAT to remit, so the AE category VAT amount must be exactly zero and must not feed the invoice VAT total.

## Solution

Set the AE cac:TaxSubtotal/cbc:TaxAmount (BT-117) to 0.00; the seller reports no VAT because the buyer accounts for it under the reverse charge mechanism.

- validate
- convert

## Valid Examples

- AE breakdown with BT-118 = AE and BT-117 = 0.00

## Invalid Examples

- AE breakdown with BT-118 = AE but BT-117 = 190.00

## Code Examples

### Valid XML
```
<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="EUR">1000.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="EUR">0.00</cbc:TaxAmount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
  </cac:TaxCategory>
</cac:TaxSubtotal>
```

### Invalid XML
```
<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="EUR">1000.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="EUR">190.00</cbc:TaxAmount>
  <cac:TaxCategory>
    <cbc:ID>AE</cbc:ID>
    <cbc:Percent>0</cbc:Percent>
  </cac:TaxCategory>
</cac:TaxSubtotal>
```

## Affected Fields

- [BT-117 VAT category tax amount](/resources/xrechnung/bt-117-vat-category-tax-amount)
- [BT-118 VAT category code](/resources/xrechnung/bt-118-vat-category-code)

## Related Rules

- [BR-AE-01](/resources/kosit-validator-errors/br-ae-01-reverse-charge-vat-breakdown-required)
- [BR-AE-08](/resources/kosit-validator-errors/br-ae-08-reverse-charge-taxable-amount-sum)
- [BR-AE-10](/resources/kosit-validator-errors/br-ae-10-reverse-charge-exemption-reason-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.