What it means
UBL lets the legal entity details of a party say with a true or false value whether it is a sole proprietorship. EN 16931 has no such flag. The only place for that kind of information is the seller's additional legal information (BT-33, cbc:CompanyLegalForm), which is free text. This rule fails whenever cbc:SoleProprietorshipIndicator is present, even if it says false.
Why it matters
This rule is a warning, so the invoice is still accepted. The recipient's software has no field for the flag and ignores it. It is worth fixing when your software adds the flag by default, or when the fact that you are a sole trader must be visible on the invoice.
How to fix it
Check the company details of your own company in your invoicing software and look for an export option that leaves out the sole proprietorship flag. If you build the XML yourself, delete cbc:SoleProprietorshipIndicator from cac:AccountingSupplierParty/cac:Party/cac:PartyLegalEntity. If the buyer needs to know, write it in cbc:CompanyLegalForm.
The rule as published
A UBL invoice should not include the AccountingSupplierParty Party PartyLegalEntity SoleProprietorshipIndicator Where this rule applies
| Rule set | Version |
|---|---|
| EN 16931 (UBL) | 1.3.17 |
| EN 16931 (UBL credit note) | 1.3.17 |
| XRechnung 3.0 (UBL) | 3.0.2 |
| XRechnung 3.0 (UBL credit note) | 3.0.2 |
| Peppol BIS Billing 3.0 (invoice) | 2026.5 |
| Peppol BIS Billing 3.0 (credit note) | 2026.5 |
| SI-UBL 2.0 / NLCIUS (invoice) | 2.0.3.13 |
| SI-UBL 2.0 / NLCIUS (credit note) | 2.0.3.13 |
| France CTC (UBL invoice) | 1.4.0-04 |
| France CTC (UBL credit note) | 1.4.0-04 |
| CIUS-RO UBL Invoice 1.0.9 | 1.0.9 |
| CIUS-RO UBL Credit Note 1.0.9 | 1.0.9 |
Check your file
Drop your e-invoice to see whether UBL-CR-181 still fails, and which other rules do.
Related rules
- UBL-CR-182 The seller's liquidation status code should be left out
- UBL-CR-183 The seller's share capital amount should be left out
- UBL-CR-184 The seller's fully paid shares flag should be left out
- UBL-CR-185 The seller's registration address should be left out
- UBL-CR-186 The seller's corporate registration scheme should be left out
- UBL-CR-187 The seller's head office party should be left out