# UBL-SR-21

Quoted from a public specification. This page is not a validator, and it is not tax, legal, or accounting advice.

- Country: EU
- Syntax: UBL
- Severity: fatal
- Statement language: en
- Last verified: 2026-10-18

## Official statement

> Payee legal registration identifier shall occur maximum once, if the Payee is different from the Seller

Source: https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/UBL-SR-21/

Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL

Severity note: fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.

## Plain-language reading

The payee legal registration identifier shall occur at most once if the payee is different from the seller. The statement has a comma and no period. It says shall, and it capitalizes Payee and Seller. The flag is fatal. The context is cac:PayeeParty. The published test counts party legal-entity company identifiers. The count comparison has a space before <= and a space after it. The test also requires the payee name to differ from the seller legal-entity registration name. That difference writes != with a space on each side. The test does not read a scheme.

## What to change

When the payee is different from the seller, send at most one payee legal registration identifier.

## Illustration

Illustration of the condition in the official statement. Not an example published by the source.

**Fails the stated condition.** The payee has two legal-entity company identifiers.

**Passes the stated condition.** The payee has one such identifier, or none, and the payee name differs from the seller legal-entity registration name.

## Published context and test

Copied from the source. Not reimplemented on this page.

```
cac:PayeeParty
```

```
(count(cac:PartyLegalEntity/cbc:CompanyID) <= 1) and ((cac:PartyName/cbc:Name) != (../cac:AccountingSupplierParty/cac:Party/cac:PartyLegalEntity/cbc:RegistrationName))
```

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