# BT-30 Seller legal registration identifier

Legal registration identifier of the seller, such as a commercial register number.

> BT-30 (Seller legal registration identifier) is the supplier's registry number — for example a German Handelsregister number (HRB) or another national company register. Optional under EN 16931 but commonly required for German invoices. Provide the qualifier and number. Example: HRB 123456.
>
> BT-30 · EN 16931 / XRechnung 3.x

## BT Reference Card

Canonical EN 16931 / XRechnung facts for this business term — citable from this anchor.

- **BT code**: BT-30
- **Name**: Seller legal registration identifier
- **Cardinality**: Optional (O)
- **Business group**: BG-4 SELLER
- **Data type**: Identifier
- **Example value**: HRB 123456

## Quick answer

Legal registration identifier of the seller, such as a commercial register number.

> **Seller details**: Who issued the invoice and how the recipient can identify that business reliably.

- validate
- convert

## In plain language

Legal registration identifier of the seller, such as a commercial register number.

Legal registration identifier of the seller, such as a commercial register number.

This gives the buyer a formal registry-based way to identify the seller as a legal entity.

## What you usually enter here

Registry identifier

Typical valid values include: HRB 12345

Optional according to EN 16931-1, but it can satisfy BR-CO-26 together with BT-29 or BT-31.

## What goes wrong often

Avoid values like:

Relevant rule codes: BR-CO-26

## Examples in context

This gives the buyer a formal registry-based way to identify the seller as a legal entity.

Optional according to EN 16931-1, but it can satisfy BR-CO-26 together with BT-29 or BT-31.

## Valid Examples

- HRB 12345

## Related Fields

This gives the buyer a formal registry-based way to identify the seller as a legal entity.

- [BT-29 Seller identifier](/resources/xrechnung/bt-29-seller-identifier)
- [BT-31 Seller VAT Identifier](/resources/xrechnung/bt-31-seller-vat-identifier)

## XML mapping and field facts

Open the technical reference if you need XML paths, validator rule codes, legal wording, or schema-specific mapping details.

### Field ID:
BT-30

### Data Type:
identifier

### Cardinality:
0..1

### Requirement:
Optional

### Max Length:
50 characters

### Since Version:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:AccountingSupplierParty/cac:Party/cac:PartyLegalEntity/cbc:CompanyID
```

### CII (UN/CEFACT) Syntax
```
/CrossIndustryInvoice/SupplyChainTradeTransaction/ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:SpecifiedLegalOrganization/ram:ID
```

## Validation Rules

### BR-CO-26
BR-CO-26

## Why the standard cares about this field

### Business Context
This gives the buyer a formal registry-based way to identify the seller as a legal entity.

### Legal Requirement
Optional according to EN 16931-1, but it can satisfy BR-CO-26 together with BT-29 or BT-31.

## Official sources and tools

- [KoSIT Validator](https://erechnungsvalidator.service-bw.de/)
- [Invoice Converter](/pdf-to-xrechnung)
- [XRechnung Standard](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)