# UBL-SR-15

> Buyer name shall occur maximum once

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-15

## Official rule text

Buyer name shall occur maximum once

## Why did my invoice fail UBL-SR-15?

The Buyer name (BT-44), the full name under which the buyer is known, may occur at most once. In UBL this is cac:AccountingCustomerParty/cac:Party/cac:PartyName/cbc:Name, which must be single-valued.

## Common causes

- Multiple cac:PartyName elements are emitted for the buyer (e.g. legal and trading names both under PartyName).
- Buyer name is duplicated from both a customer-master name and an order contact name.
- Template loops over buyer aliases and outputs each as a PartyName.

## How do I fix it?

```
Provide a single buyer name: <cac:AccountingCustomerParty><cac:Party><cac:PartyName><cbc:Name>Buyer Corp GmbH</cbc:Name></cac:PartyName></cac:Party></cac:AccountingCustomerParty> and remove extra cac:PartyName elements.
```