Which documents you need from every subcontractor
Before commissioning a subcontractor (Nachunternehmer, NU), general contractors in Germany must collect tax certificates (the §48b Freistellungsbescheinigung — a withholding tax exemption certificate, the USt 1 TG certificate, a Finanzamt clearance), social fund clearance certificates (from the Krankenkassen — the health insurance funds, BG BAU — the construction trade association, and SOKA-BAU — the construction industry social fund), labor law declarations (a Mindestlohn — minimum wage — commitment, the Nachunternehmererklärung — subcontractor declaration, A1 certificates where applicable), as well as trade and insurance proofs (trade registration, Handwerksrolle entry, business liability insurance, commercial register extract) — and keep them current throughout the project. Each of these documents stands for a concrete liability risk: 15 % Bauabzugsteuer — construction withholding tax (§48 EStG), guarantor liability for social security contributions (§28e SGB IV), minimum wage liability (§13 MiLoG), fines under the German act against undeclared work (SchwarzArbG). Collect the full list and keep it current, and the bulk of your compliance work as a general contractor is done.
Tax certificates
| Document | Issued by | Typical validity |
|---|---|---|
| Freistellungsbescheinigung §48b EStG (withholding tax exemption certificate) | Finanzamt (tax office) | Time-limited, max. 3 years — track the expiry date! |
| USt 1 TG certificate (proof of construction-service status for the §13b UStG reverse charge) | Finanzamt | Max. 3 years |
| Unbedenklichkeitsbescheinigung Finanzamt (tax office clearance certificate) | Finanzamt | Snapshot only — renew annually |
The §48b certificate is the single most important document on the list: if it is not on file at the moment of payment, you must withhold 15 % Bauabzugsteuer (construction withholding tax) — otherwise you are personally liable under §48a para. 3 EStG. Our step-by-step guide to verifying a Freistellungsbescheinigung (in German) shows how to check authenticity and validity with the Federal Central Tax Office.
Social security & social funds
| Document | Issued by | Typical validity |
|---|---|---|
| Unbedenklichkeitsbescheinigung Krankenkasse(n) (health insurance fund clearance) | Collection agencies (Einzugsstellen) | 1–3 months — request regularly |
| Unbedenklichkeitsbescheinigung BG BAU (clearance from the construction trade association — Berufsgenossenschaft) | BG BAU | 3 months |
| Unbedenklichkeitsbescheinigung SOKA-BAU (construction industry social fund clearance) | SOKA-BAU | Reference-date based — renew continuously |
Behind these three certificates sits the guarantor liability for social security contributions under §28e SGB IV (guide in German): if your subcontractor fails to pay their contributions, the collection agency can pursue you like a directly liable guarantor. Current clearance certificates are your central means of exoneration — but only as long as they are no more than a few weeks old. The specifics of SOKA-BAU (holiday fund contributions, the reference-date principle) are covered in our dedicated guide.
Labor law & personnel
- Mindestlohn commitment declaration — signed by the subcontractor, including the obligation to pass it down to their own subcontractors. The backdrop is the no-fault general contractor liability for the minimum wage (§13 MiLoG; guide in German).
- Nachunternehmererklärung / self-disclosure — master data, register entries, and commitment declarations in a single document; the linked guide includes a free Word template.
- A1 certificates for each posted worker of a foreign subcontractor — issued per person and per posting, and the first document customs asks for at any inspection.
- Residence and work permits for workers from non-EU countries — everything else to watch with foreign subcontractors in Germany is covered in its own guide.
Trade & insurance
- Gewerbeanmeldung (trade registration) — the registered scope of activity must match the trade being commissioned.
- Handwerkskarte / entry in the Handwerksrolle (German register of licensed crafts) for trades requiring licensing (Annex A HwO) — the linked guide (in German) shows how to verify the entry online.
- Business liability insurance confirmation (Betriebshaftpflicht; guide in German) — check coverage amounts, insured activity, and policy term, or your recourse will run dry when damage occurs.
- Commercial register extract (Handelsregisterauszug) — verify the signing authority of whoever signs the contract.
- Optional: prequalification certificate (PQ-VOB) (in German) — replaces many individual proofs, especially on public contracts.
How to organize the process
- Define a standard: one binding document list for all subcontractors — no exceptions, not even for "long-standing partners".
- Collect before signing: no work starts without a complete file. The Nachunternehmererklärung with a tick-box document list turns this into a fixed workflow.
- Track deadlines: every expiry date with reminders 30/14/7 days ahead — how to start with Excel and when software becomes necessary is covered in our guide to deadline management for subcontractor certificates (in German).
- Tie payment to compliance: expired mandatory documents = payment hold until they are resubmitted. The contractual retention right belongs in the subcontractor declaration.
- Archive audit-proof: who submitted what, and when — fully traceable for tax audits, the FKS (Finanzkontrolle Schwarzarbeit — the customs unit that polices undeclared work), and your clients.