The short answer
Changing who does the bookkeeping — from the tax adviser to a service provider, from outsourced to in-house or the other way round — is not a software question. It is a handover question. Three things decide it: a clean cut-off date, complete data, and a settled way of getting at the history.
The best moment is the start of a financial year, because the opening balance sheet and the current year then coincide. The second best is the start of a quarter.
A note for readers outside Germany
In most markets the incumbent bookkeeper is a vendor. In Germany it is usually a Steuerberater, a regulated profession, and that changes three things about the switch.
- Bookkeeping and the annual accounts are normally bundled — and can be separated. The same adviser typically does the monthly books, the statutory accounts and the tax returns. Splitting them is standard and often the right answer: a service provider runs the ongoing bookkeeping, the Steuerberater keeps the accounts and the tax filings. Most foreign parents do not realise this is a choice they have.
- Unpaid fees can hold your documents. German law gives a tax adviser a right of retention over documents while fees are outstanding. In practice this is the single most common reason a switch stalls for weeks. Settle every open invoice before you ask for the handover, not after.
- The ledger lives in the adviser's system. German bookkeeping runs largely on DATEV, which belongs to the adviser, not to you. Ask for the export in the accounting system's own format and name it in writing. PDFs of reports are not a usable history — and you will want the history in the next tax audit or buyer review.
One more thing that does not move: the statutory duty to retain the records stays with the company whatever the arrangement. An archive login at the old provider that expires with the contract is not compliance.
The typical triggers
- Figures arrive too late. A monthly close that regularly lands after three weeks cannot be steered with.
- No one to ask. Queries take days and the person handling them changes.
- Growth. What worked at 200 documents a month does not hold at 1,500.
- New requirements. Investor reporting, consolidation, foreign VAT, an audit obligation.
- A system change. A new ERP makes the existing division of labour obsolete anyway.
The sequence, in six steps
- Set the cut-off and give notice. Check the notice period, confirm the switch in writing and name the date from which the new provider books.
- Request the data release — specifically. Trial balance, account descriptions, general ledger detail, open items for receivables and payables, the fixed asset register with acquisition values and remaining useful lives, posting journals, master data, and the source documents in their original format.
- Reconcile the opening balances. The new provider takes over the balances and checks them against the last statutory accounts. Every difference gets settled now, not in the year-end close.
- Fix the chart of accounts and the posting logic. A switch is the best opportunity to clean up the chart of accounts and align the reporting structure with what management actually needs. Afterwards it becomes expensive.
- Set up processes and access. Invoice intake, approvals, bank access, interfaces from upstream systems, permissions.
- Run the first month in parallel. The first close is sense-checked against the previous logic. Differences are normal — they only have to be explainable.
The data handover is the critical point
Records and data relevant for tax belong to the company, not to the provider. Friction still arises regularly, usually for three reasons: unpaid fees, inconsistent export formats, and the question of whether reports are released in their original format or only as PDF.
Three things prevent most of it. Put the right to a data export in the accounting system's own format into the contract at the outset. Clear open invoices before the switch. And obtain the handover in full, and check it, before any access is switched off.
Retention and access to the history
Statutory retention obligations stay with the company regardless of who does the booking. A switch therefore includes a decision about where the old data sits and who can reach it — ideally a storage location of your own, independent of any provider. An archive login at the outgoing provider that expires on termination is not a solution.
The five mistakes
- Switching mid-year with no interim close. Without clean interim figures it becomes impossible later to tell whose posting came from where.
- Underestimating the fixed asset register. Missing remaining useful lives and acquisition dates are the most common reconstruction work of all.
- Taking over open items unreconciled. Receivables without an ageing structure mean collections stop working for months.
- Closing access too early. Receive and verify the data in full first, then end the access.
- Carrying the chart of accounts across unchanged. Every accumulated imprecision travels with it, and the reports stay as unusable as before.
Common questions
How long does a switch take?
From the decision to the first close of your own, typically six to ten weeks, most of it spent on the data release and reconciling the opening values. Setting up the system itself takes days.
Does the tax adviser have to change too?
No. Bookkeeping and the annual accounts can be separated: a service provider runs the ongoing books while the Steuerberater prepares the statutory accounts and tax returns. What matters is defining the interface cleanly — who delivers what, by when.
Can our tax adviser refuse to hand over the data?
German law gives tax advisers a right of retention over documents while fees are outstanding, so an unpaid invoice can hold up the handover. Settle the account first, request the release in writing and in a named format, and keep access open until the data has arrived and been checked. Where a handover is genuinely disputed, take legal advice rather than escalating on your own.
What does the switch cost?
The one-off effort sits in the data migration and in clearing legacy issues. It rises the less complete the handover is, which is why preparation almost always pays for itself. On the ongoing cost: what outsourced bookkeeping costs.
Is a switch sensible before a transaction?
Not immediately before. A live buyer review needs continuity and fast answers. The sensible moment is twelve months ahead, when reporting and evidence are being brought up to transaction standard anyway — see the data room for financial due diligence.
Who is responsible for retaining the records afterwards?
The company, always. Outsourcing the bookkeeping does not outsource the retention duty. Plan for a storage location you control, and do not rely on an archive login that ends with the contract.
Read on
- What outsourced bookkeeping costs – pricing models and cost drivers.
- Closing backlog and fast close – what becomes possible after the switch.
- The first statutory audit in Germany – why the history has to stay reachable.
- Exit readiness – the twelve-month window a switch fits into.
- Preparing for a German bank meeting – who reads the monthly figures and how quickly.
- Accounting as a Service · Implementing finance software.
Sources and status
Based on nugrow's mandate experience in taking over ongoing bookkeeping, and on common German practice for tax-adviser engagements, data release and record retention. As of September 2026. This article is an overview and does not replace tax or legal advice; retention and data-release questions belong in front of an adviser in the individual case.
