# 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

Key EN 16931 and XRechnung facts for this business term.

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

## Seller details

Who issued the invoice and how the recipient can identify that business reliably.

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-30)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-30)

## In plain language

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.

## Where the field sits

BT-30 belongs to the Seller part of the invoice. UBL 2.1 Syntax: Invoice › cac:AccountingSupplierParty › cac:Party › cac:PartyLegalEntity › cbc:CompanyID. CII (UN/CEFACT) Syntax: rsm:CrossIndustryInvoice › rsm:SupplyChainTradeTransaction › ram:ApplicableHeaderTradeAgreement › ram:SellerTradeParty › ram:SpecifiedLegalOrganization › ram:ID.

## What goes wrong often

Relevant rule codes: BR-CO-26

## Valid Examples

- HRB 12345

## Related Fields

- [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

## XML Implementation

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

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

## Validation Rules

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

## Check whether your XRechnung sets BT-30 correctly

Upload the XML file to the free validator. It applies the KoSIT rules for XRechnung 3.0 and names each finding with its rule ID, for this field for example BR-CO-26. Creating a new invoice instead? The converter checks the invoice against the same rules and shows the findings before download.

- [Validate XML](/en/xrechnung-validator)
- [Convert invoice](/en/pdf-to-xrechnung)

Free, no account needed. XML file up to 2 MB.

## Official sources and tools

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