# BT-28 Seller trading name

Trading or brand name of the seller when it differs from the legal seller name.

> BT-28 (Seller trading name) is the commercial or "doing business as" name shown to customers when it differs from the legal name (BT-27). Optional under EN 16931. Useful for groups that invoice under a parent legal entity but trade under a brand. Example: Muster Trading.
>
> BT-28 · EN 16931 / XRechnung 3.x

## BT Reference Card

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

- **BT code**: BT-28
- **Name**: Seller trading name
- **Cardinality**: Optional (O)
- **Business group**: BG-4 SELLER
- **Data type**: Text
- **Example value**: Muster Trading

## Quick answer

Trading or brand name of the seller when it differs from the legal seller name.

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

- validate
- convert

## In plain language

Trading or brand name of the seller when it differs from the legal seller name.

Trading or brand name of the seller when it differs from the legal seller name.

This field helps recipients recognize the seller under the market-facing name they actually know.

## What you usually enter here

Trading or brand name

Typical valid values include: Invoice Converter

Optional according to EN 16931-1.

## What goes wrong often

Avoid values like: , AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Examples in context

This field helps recipients recognize the seller under the market-facing name they actually know.

Optional according to EN 16931-1.

## Valid Examples

- Invoice Converter

## Invalid Examples

- AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Related Fields

This field helps recipients recognize the seller under the market-facing name they actually know.

- [BT-27 Seller Name](/resources/xrechnung/bt-27-seller-name)

## 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-28

### Data Type:
text

### Cardinality:
0..1

### Requirement:
Optional

### Max Length:
200 characters

### Since Version:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:AccountingSupplierParty/cac:Party/cac:PartyName/cbc:Name
```

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

## Why the standard cares about this field

### Business Context
This field helps recipients recognize the seller under the market-facing name they actually know.

### Legal Requirement
Optional according to EN 16931-1.

## 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)