What it is
The OVT-tunnus (literally "OVT identifier," where OVT stands for Organisaatioiden välinen tiedonsiirto — "data interchange between organisations") is the Finnish electronic-invoicing address used to route invoices to a specific organisation. It predates Peppol — it has been in use since the 1990s through TIEKE, the Finnish Information Society Development Centre — and has been folded into the Peppol ecosystem as the standard Finnish participant identifier.
The format is:
0037 + Y-tunnus (8 digits, no dash) + optional 5-character suffix
Minimum length is 12 characters (0037 + Y-tunnus). Maximum is 17 (with the suffix). The Y-tunnus is the Finnish Business ID, normally written with a dash like 1234567-8; in an OVT-tunnus the dash is removed, producing 12345678. The optional suffix can be alphanumeric and is used by larger organisations to route invoices to specific departments or subsidiaries.
Example: a company with Y-tunnus 2069746-9 has an OVT-tunnus of 003720697469, optionally suffixed (e.g. 00372069746900001 for one business unit).
OVT and Peppol — the scheme-ID change
Finland's relationship between OVT codes and Peppol identifiers shifted in late 2023 / early 2024, and the change is the single most-asked question from ERP teams integrating with Finland.
Old setup. The OVT code was registered as Peppol scheme ID 0037, originally meaning "the Finnish tax authority code." A Finnish Peppol participant identifier looked like 0037:003712345678.
New setup. Finland migrated to a new ICD (Issuing Code Designator) scheme ID 0216, registered explicitly as "OVT code (Finland)" with the ISO 6523 / ISO/IEC 6523 registry. Finnish Peppol participant identifiers are now formatted 0216:003712345678 — the prefix 0037 is no longer the Peppol scheme ID, it is the leading digits of the OVT code itself.
The practical consequences:
0037:... were migrated; the old scheme is now legacy.0216 as the schemeID (BT-49 / BT-34 electronic-address scheme ID), not 0037.EndpointID element still begins with 0037 because that is part of the OVT format itself.0037:003712345678 will either be rejected at the access point or fail SMP lookup.This is the kind of detail that breaks integrations silently — the invoice goes out, the access point accepts it, but no SMP entry exists at the old scheme so the document never arrives. Always test against the live SMP/SML lookup before going live.
Who administers it
Finland's e-invoicing mandate
Finland was one of the earliest EU adopters of mandatory e-invoicing. The Act on Electronic Invoicing (Laki sähköisestä laskutuksesta 241/2019) entered into force on 1 April 2020 and gave every public-sector body and every business the right to demand electronic invoices in an EN 16931-conformant format. Public-sector buyers are obliged to accept; private-sector buyers can be required to accept by any supplier who insists.
In practice this turned Finland into a de facto B2B e-invoicing market years before most of the EU caught up — over 90% of B2B invoice volume in Finland is now electronic, almost all of it carrying an OVT-tunnus as either the sender or receiver address.
How it appears in an EN 16931 invoice
In UBL, the OVT code appears as the value of cbc:EndpointID with schemeID="0216" (or, in legacy data, schemeID="0037"):
003712345678
In CII, the equivalent is the ram:URIID element under ram:URIUniversalCommunication, with the matching scheme attribute.
The scheme ID is BT-49-1 (for the buyer's electronic address) or BT-34-1 (for the seller's). Getting the scheme ID right is at least as important as getting the OVT code itself right — Peppol routing fails if either is wrong, and the resulting error messages typically point at the wrong field.
Common pitfalls
0037 scheme ID after the migration. Failed SMP lookup; the invoice never arrives. Always check the live Peppol SMP / verkkolaskuosoite.fi entry before issuing the first production invoice.0037 1234567-8 is malformed; the OVT format is 0037 12345678 (no dash).Relation to EN 16931
EN 16931 does not mandate any specific identifier scheme — it accepts any registered ICD that maps to BT-49-1 / BT-34-1. The Finnish OVT-tunnus is one of dozens of national schemes (alongside Leitweg-ID, Codice Destinatario, KVK number, Enterprise Number Belgium, SIRET, GLN). What makes OVT distinctive is that Finland's early mandate produced an unusually high level of cross-network coverage — almost every Finnish business has a registered OVT, and TIEKE's lookup service makes verification cheap.
For ERP vendors onboarding Finnish customers, the right sequence is: collect the customer's Y-tunnus, look up their OVT-tunnus and Peppol participant ID at verkkolaskuosoite.fi, store both in master data with the scheme ID, and validate the lookup periodically. The Y-tunnus is stable; the OVT can change with restructures; the Peppol scheme ID changed once already and could change again.