# BR-E-02 Exempt invoice line requires a seller tax identifier

An invoice with an invoice line (BG-25) where the invoiced item VAT category code (BT-151) is "Exempt from VAT" (E) 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

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

## Context and Significance

This EN16931 rule governs VAT exemption (category E): a seller who applies an exemption must be tax-identified so the tax authority can verify the exempt supply. In practice, the error often affects exempt sellers whose master data holds no VAT number, such as small businesses under § 19 UStG in Germany, medical practices or training providers: a national tax number in BT-32 is enough.

## Solution

Provide at least one seller tax identifier — BT-31, BT-32 or BT-63 — on the invoice whenever an exempt (E) line is present.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-E-02)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-E-02)

## Valid Examples

- Exempt line (BT-151 = E) with seller BT-31 = DE123456789

## Invalid Examples

- Exempt line (BT-151 = E) with no BT-31, BT-32 or BT-63 anywhere on the invoice

## Code Examples

### Valid XML
```
<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyTaxScheme>
      <cbc:CompanyID>DE123456789</cbc:CompanyID>
      <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
    </cac:PartyTaxScheme>
  </cac:Party>
</cac:AccountingSupplierParty>
<cac:InvoiceLine>
  <cac:Item>
    <cac:ClassifiedTaxCategory><cbc:ID>E</cbc:ID><cbc:Percent>0</cbc:Percent><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:ClassifiedTaxCategory>
  </cac:Item>
</cac:InvoiceLine>
```

### Invalid XML
```
<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyLegalEntity><cbc:RegistrationName>Seller GmbH</cbc:RegistrationName></cac:PartyLegalEntity>
  </cac:Party>
</cac:AccountingSupplierParty>
<cac:InvoiceLine>
  <cac:Item>
    <cac:ClassifiedTaxCategory><cbc:ID>E</cbc:ID><cbc:Percent>0</cbc:Percent><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:ClassifiedTaxCategory>
  </cac:Item>
</cac:InvoiceLine>
```

## 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)

## Related Rules

- [BR-E-03](/resources/kosit-validator-errors/br-e-03-exempt-allowance-seller-vat-id)
- [BR-E-10](/resources/kosit-validator-errors/br-e-10-exempt-breakdown-reason-required)
- [BR-E-05](/resources/kosit-validator-errors/br-e-05-exempt-vat-rate-must-be-zero)

## 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.