# UBL-SR-40

> Buyer trade name shall occur maximum once

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-40

## Official rule text

Buyer trade name shall occur maximum once

## Why did my invoice fail UBL-SR-40?

The Buyer trade name (BT-45) is the buyer's commonly used or trading name, distinct from its legal registration name. EN 16931 allows at most one buyer trade name, so cac:AccountingCustomerParty/cac:Party/cac:PartyName/cbc:Name must not occur more than once. Additional identifiers belong in other party fields, not in extra PartyName elements.

## Common causes

- Two cac:PartyName/cbc:Name elements under the buyer party.
- Both a trading name and a department name written as separate PartyName elements.
- Trade name duplicated per language for the buyer.

## How do I fix it?

```
Keep one buyer trade name: <cac:AccountingCustomerParty><cac:Party><cac:PartyName><cbc:Name>Acme Retail</cbc:Name></cac:PartyName>...</cac:Party></cac:AccountingCustomerParty>.
```