# BR-S-02 Standard-rated line requires a seller tax identifier

An invoice that contains an invoice line (BG-25) whose invoiced item VAT category code (BT-151) is "Standard 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

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

## Context and Significance

This EN16931 rule applies to category S supplies, which cover the standard rate and reduced rates (for example 19 % and 7 % in Germany). A seller who charges VAT must be identifiable for tax purposes. In practice, the error occurs when the company master data in the invoicing software holds neither a VAT identifier nor a tax number, or when the export does not write them into cac:PartyTaxScheme.

## Solution

Add the seller VAT identifier in cac:PartyTaxScheme/cbc:CompanyID (BT-31), or provide the seller tax registration identifier (BT-32) or the tax representative VAT identifier (BT-63).

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

## Valid Examples

- Standard-rated line at 19 % with seller VAT identifier DE123456789 present

## Invalid Examples

- Standard-rated line at 19 % but the seller party carries no BT-31, BT-32 or BT-63

## 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>S</cbc:ID><cbc:Percent>19</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>S</cbc:ID><cbc:Percent>19</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)
- [BT-151 Invoiced item VAT category code](/resources/xrechnung/bt-151-invoice-line-vat-category-code)

## Related Rules

- [BR-S-1](/resources/kosit-validator-errors/br-s-01-standard-rated-items-require-standard-rated-vat-breakdown)
- [BR-S-03](/resources/kosit-validator-errors/br-s-03-standard-rated-allowance-seller-vat-id)
- [BR-S-04](/resources/kosit-validator-errors/br-s-04-standard-rated-charge-seller-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.