SOKA-BAU and subcontractors: contributions, guarantor liability, certificates

Who is subject to SOKA-BAU?

Companies in the main construction trades whose working time is predominantly spent on construction activities as defined by the VTV (the collective agreement governing the social fund scheme) must participate in the scheme — regardless of any union or employer-association membership, because the VTV has been declared universally binding. This also applies to foreign companies posting workers to Germany (via the holiday fund scheme, Urlaubskassenverfahren) — for the other obligations that come with posting workers, see our guide to foreign subcontractors in Germany.

The general contractor's guarantor liability

SOKA contributions (in particular the holiday fund scheme) are secured through §14 AEntG: the general contractor (Generalunternehmer, GU) is liable for the minimum holiday pay and the associated social fund contributions of its subcontractors like a first-demand guarantor (selbstschuldnerischer Bürge) — across every tier of the chain. SOKA-BAU pursues these claims actively and is noticeably more persistent than many a tax office (Finanzamt). How this guarantor liability fits into the broader general contractor liability for social security contributions (in German) is covered in a separate article.

The SOKA clearance certificate

The SOKA-Unbedenklichkeitsbescheinigung (clearance certificate) confirms that the company is registered with SOKA-BAU and meeting its reporting and contribution obligations. Check three things:

• Date of issue — as a snapshot certificate, it should be no older than 3 months
• Company account number — does it match your contracting party?
• Restrictions — take notes about deferred payments or pending proceedings seriously

Special case: not every subcontractor is subject to SOKA

Pure electrical, plumbing/HVAC, or metal construction firms fall under their own social funds or none at all. In these cases, require a written declaration from the subcontractor stating that it is not subject to contributions, with reasons — this documents that you examined the question instead of ignoring it.

Ongoing monitoring instead of a one-time check

1. SOKA certificate (or a reasoned negative declaration) before construction starts — as part of the complete subcontractor document checklist
2. Renewal every 3 months, locked in by contract on long projects — best handled through systematic deadline management for certificates (in German)
3. For foreign subcontractors: proof of participation in the holiday fund scheme — alongside the A1 certificate (A1-Bescheinigung) for each posted worker
4. Cross-check: does the reported headcount match the crew size on site?
5. Gapless archiving in case you are ever held liable