Structured payment communication (OGM) in Belgium

A Belgian convention for machine-readable payments

When a Belgian customer pays an invoice by bank transfer, the payment instruction carries a structured communication (communication structurée / gestructureerde mededeling, often abbreviated OGM in Dutch-speaking contexts). It is not a legal invoice field in the narrow VAT sense, but it is one of the most consequential operational identifiers in domestic B2B trade.

The visible form is immediately recognizable: +++123/4567/89012+++. Those slashes and plus signs are not decorative. They signal to banks and accounting software that the reference follows a fixed twelve-digit scheme with a mathematical check, so incoming transfers can be matched to open receivables without manual interpretation.

For freelancers and SMEs issuing dozens or hundreds of invoices per month, the structured communication is often the difference between automatic reconciliation and a weekly afternoon spent matching amounts to debtors by guesswork.

Format, check digits, and why errors are rejected

Belgian structured communications contain twelve digits in total:

The first ten digits encode the payload — typically an invoice number, customer code, or sequential reference. The last two digits are a modulo-97 check on those ten digits (use 97 when the remainder is zero). This catches typing errors and lets systems reject malformed references before they reach the ledger.

The canonical display is +++AAA/BBBB/CCCCX+++. SEPA transfers carry the same twelve digits in the structured remittance information field (ISO 20022).

Structured payment communication (OGM)

A standardized twelve-digit Belgian payment reference with modulo-97 check digits, formatted as +++123/4567/89012+++, used to link bank transfers automatically to invoices or customer accounts.

From invoice to bank statement: the matching chain

Understanding OGM requires seeing the full chain from outbound invoice to inbound bank movement.

On the invoice

Belgian invoicing practice places the structured communication prominently — usually near payment instructions alongside the IBAN and BIC. The payer is expected to copy it verbatim into the transfer's communication or reference field. Many invoicing platforms generate the reference automatically when an invoice is finalized, binding it to the invoice number or an internal receivables key.

The reference does not replace the invoice number for VAT or audit purposes. Invoice numbering remains governed by continuity and legal mention rules. The OGM is a payment-layer identifier: optimized for banking rails, not for tax evidence.

In the payer's bank

When the customer initiates a SEPA credit transfer, the structured communication travels as machine-readable remittance data. Belgian retail and business banking interfaces recognize the format and often validate the check digits at entry time, reducing the incidence of unreconcilable payments.

On the supplier's bank statement

On the receiving side, Belgian banks export movements in CODA (legacy flat-file) or ISO 20022 camt.053 formats. Both can expose structured remittance information as a distinct, parseable field rather than burying it in free-text narrative.

Accounting software reads this field to propose matches against open invoices. The operational principle is simple: the same identifier on the invoice and on the bank line, validated by checksum, crossing the payment network unchanged.

Distinction from free-text references and foreign payments

A free-text communication allows arbitrary payer messages. Banks store it, but matching becomes fuzzy. Structured communication trades expressive flexibility for deterministic automation. Domestic Belgian B2B is where OGM delivers the highest reconciliation yield; cross-border SEPA practice varies.

Why SMEs should treat OGM as infrastructure

As invoice volume grows, manual reconciliation costs time, produces allocation errors, and obscures cash flow. OGM addresses matching at the point of payment — before entries hit the general ledger. Combined with Peppol invoicing and CODA/camt bank import, it closes the loop between structured bills out and structured receipts in. PDF-only businesses still benefit, because payment rails are independent of invoice delivery channel.

1. Generate automatically — software must compute check digits.
2. One reference per invoice for standard B2B receivables.
3. Display prominently on every invoice and reminder.
4. Configure bank import to prioritize structured remittance fields.

Relation to e-invoicing and accounting discipline

Belgium's structured e-invoicing mandate (Peppol, EN 16931) modernizes how invoice data travels between businesses. OGM modernizes how money is linked back to that data. The two layers complement each other:

An SME that masters Peppol but ignores OGM may still reconcile manually; OGM alone already removes a major treasury pain point. Together they reduce manual touchpoints across order-to-cash.

Structured communication guarantees identification, not payment. Partial payments, grouped remittances, and credit notes still need exception handling. The check digit validates format, not amount. For numbering schemes, factoring, or direct debit, consult your accountant — Febelfin documents the convention, but your chart of accounts determines how matches post.