The Forschungszulage goes through two separate assessment procedures. The Bescheinigungsstelle Forschungszulage (BSFZ) establishes whether a project qualifies on the merits. The tax office then assesses the amount of the allowance, and the tax audit arrives when both appear long since settled. Anyone unable to produce robust records at that point risks clawback.
The two-stage procedure and its assessment logic
The BSFZ certificate is a basic assessment notice under § 171 (10) AO. It binds the tax office on whether the project qualifies on the merits, not on the level of expenditure. The tax office assesses the assessment base independently during assessment and again in a tax audit.
That produces a clear dividing line: a positive BSFZ decision doesn't protect you against reductions in a tax audit. It only protects the finding on the merits, namely whether the project is research within the meaning of the FZulG. The question of how many hours who worked on it, and whether those costs can be evidenced, isn't answered by the BSFZ decision.
What the tax office examines in an audit
The tax audit targets three areas.
- Staff expenditure: the tax office requires timesheets or equivalent activity records attributing every claimed R&D hour to a certified project. Payslips alone aren't enough; they evidence the cost but not the R&D link.
- Contract research: for contracts awarded after 27 March 2024, 70 per cent of the fee feeds into the assessment base (§ 3 (4) FZulG). The tax office checks whether contracts and invoices attribute the subject of the work unambiguously to the R&D project. Mixed invoices combining development and series production lead to reductions.
- Cumulation with other aid: the tax office checks whether the same expenditure has already been funded under another aid scheme. The ban on cumulation under § 7 FZulG applies at the level of the individual cost centre, not at project level.
The application decree on the FZulG (the Ministry of Finance circular of 7 February 2023) sets out which documents the tax office can require during assessment and in an audit. It does accept reconstruction of time records after the fact in principle, but requires a robust derivation, not a mere estimate.
Time records: the critical evidence
Without complete, contemporaneous time records the tax office won't accept the staff costs claimed. That is the most common cause of reductions in a tax audit.
Contemporaneous means the records should be created during the R&D work, not after the year end. What can be used for a reconstruction after the fact: Git commit history with author attribution, ticket systems such as Jira or Linear with project attribution, calendar entries, pull request data, meeting minutes. Several agreeing sources make a derivation of R&D shares credible. A single source is rarely enough.
A separate mechanism applies to shareholder-managing directors: under § 3 (3) FZulG they claim notional own work, capped at 40 hours a week. Here too an hour-by-hour record per project is required. Without a written basis, a ratio passed on verbally won't hold up in an audit.
From 2026, a further 20 per cent of eligible expenditure may be claimed as flat overheads (§ 3 (3b) FZulG), with no itemised evidence. That item is audit-resilient because it doesn't rest on time records.
The ban on cumulation: ZIM and other aid
§ 7 FZulG prohibits double funding: expenditure already funded under a state aid scheme may not additionally feed into the Forschungszulage assessment base.
The practically relevant situation is combination with the Zentrales Innovationsprogramm Mittelstand (ZIM). Anyone drawing a ZIM grant and the Forschungszulage on the same project has to keep a clean separation in the cost plan and the accounts, at the level of the person-hour or the invoice line, not just at project level. The same applies to EXIST-funded staff costs and other state programmes.
In an audit the tax office asks for the other programme's funding decision and compares the funded cost items against the Forschungszulage assessment base. Anyone who hasn't documented the delimitation already at the bookkeeping level is left explaining.
SME status under audit scrutiny
The ten-percentage-point SME uplift under § 4 FZulG — 35 instead of 25 per cent — depends on SME status under Annex I of the General Block Exemption Regulation (GBER). The conditions: fewer than 250 employees and annual turnover up to €50 million or a balance sheet total up to €43 million.
The audit examines that status because it decides up to €1.2 million of annual funding when the assessment base is fully used. Two situations come up regularly.
- Linked companies: with holdings above 50 per cent or a controlling relationship, the linked company's employees, turnover and balance sheet total are fully attributed. A nominally small company can lose SME status through a parent group even though it is below all the thresholds itself.
- Public shareholdings: if a public body holds more than 25 per cent, the company is not an SME within the meaning of the GBER, subject to narrow exceptions.
Anyone who claimed the SME uplift but can't evidence the conditions has to repay the difference. GBER-compliant documentation of SME status therefore belongs in the file with the Forschungszulage application.
Retention periods and limitation of assessment
The tax assessment period is four years under § 169 (2) no. 2 AO. It doesn't begin at the end of the financial year but only at the end of the year in which the tax return was filed. In practice that means records for the Forschungszulage regularly have to still exist and be accessible seven to ten years after the end of the financial year concerned.
While a BSFZ application is pending, the open basic assessment notice suspends the running of the assessment period under § 171 AO. That extends the tax office's audit window accordingly. Anyone with several annual applications running at the BSFZ in parallel should keep the suspension in view explicitly per financial year.
For an audit, that produces a simple rule: all records that close the chain from the BSFZ certificate through the project description to the time records, payslips, contracts and fixed asset accounting have to be kept for as long as the tax assessment can still be challenged or amended. Complete documentation isn't only an obligation; it is the only robust protection against clawback that can arrive years after the BSFZ decision.
FAQ
What does the tax office examine on the Forschungszulage in an audit?
The tax office independently examines the assessment base: staff costs, own work and contract research fees. It requires time records attributing every R&D hour to a certified project, plus payslips, contracts and evidence that there is no double funding under § 7 FZulG.
Can the Forschungszulage be clawed back after an audit?
Yes. If the audit finds that staff hours claimed weren't demonstrably attributed to a qualifying project, or that double funding occurred, the tax office reduces the allowance accordingly or reclaims the amount over-assessed.
How long do I have to keep Forschungszulage records?
At least as long as the tax assessment period runs. Under § 169 (2) no. 2 AO that is four years, but it only begins at the end of the year in which the tax return was filed. In practice that regularly means a retention period of seven to ten years after the end of the financial year concerned.
Is the BSFZ certificate enough as evidence in an audit?
No. The BSFZ certificate is a basic assessment notice under § 171 (10) AO and binds the tax office on whether the project qualifies on the merits. It says nothing about the level or composition of the expenditure. That needs separate records: timesheets, payslips, contracts, account statements.
What happens if the Forschungszulage and ZIM are claimed on the same project?
That is prohibited under § 7 FZulG to the extent the same expenditure is already funded through ZIM or another state aid scheme. The tax office reduces the assessment base accordingly. The permissible solution is a clean cost separation at the level of the person-hour or the invoice line, not just at project level.
Forschungszulage 2026: the complete guide
A €12m assessment base, a 35% SME rate, a two-stage procedure: an overview of the Forschungszulage in 2026, and where to find the detail.
Forschungszulage: keeping time records properly
Without complete time records the tax office won't accept the staff costs. How the documentation has to be structured, which formats work, and what a tax audit looks for.
Forschungszulage: which staff costs are eligible
Which pay components feed into the assessment base, how the 20% overhead flat rate works from 2026, and why time records decide the payout.
Forschungszulage retroactively: four years of cash flow almost nobody claims
§ 169 AO allows closed financial years to be reopened. What the typical bootstrapped founder overlooks.
All the detail, eligibility and pitfalls:
- [1]Research Allowance Act (FZulG) — consolidated version— Federal Ministry of Justice · gesetze-im-internet.de, 2026 Source
- [2]Ministry of Finance circular of 7 February 2023 on granting the Forschungszulage under the FZulG (AEFZulG)— Federal Ministry of Finance, 2023 Source
- [3]Fiscal Code § 169 — limitation of assessment— Federal Ministry of Justice · gesetze-im-internet.de, 2024 Source
- [4]Fiscal Code § 171 — suspension of the limitation period— Federal Ministry of Justice · gesetze-im-internet.de, 2024 Source
- [5]FAQ — assessment criteria and application procedure for the Forschungszulage— Bescheinigungsstelle Forschungszulage (BSFZ), 2026 Source
- [6]Assessment guide of the Bescheinigungsstelle Forschungszulage (as at October 2025)— Bescheinigungsstelle Forschungszulage (BSFZ), 2025 Source
- [7]Annex I of the General Block Exemption Regulation (Regulation (EU) No 651/2014) — the SME definition— EUR-Lex / European Commission, 2014 Source