Dealing with the local tax office - Is a tax auditor allowed to request a company’s e-mail correspondence?
In the context of an external tax audit, the tax auditor is normally provided with incoming and outgoing invoices as well as the documentation related to the annual financial statements. However, in the course of ongoing digitalisation, e-mail correspondence has likewise gained substantially in importance. This is attributable in particular to the fact that electronic communication frequently happens more freely and is less formal than traditional correspondence. It is therefore not surprising that tax auditors are increasingly requesting access to the e-mail communications of an audited company. It is however open to question whether there is a legal basis for this.
Legal basis for retention obligations
A recent ruling by the Federal Fiscal Court (Bundesfinanzhof, BFH) of 30.4.2025 (case reference: XI R 15/23) explained its position on this matter. According to Section 147(1) of the Fiscal Code (Abgabenordnung, AO), specific documents have to be retained and, upon request, submitted to the auditor (Section 200(1) sentence 2 AO). These include, in particular, accounting documents - thus, incoming and outgoing invoices - as well as annual financial statements together with the related documents (Section 147(1) nos. 1 and 4 AO). Furthermore, trade and business correspondence that has been received and sent as well as other documents have to be retained to the extent that these are of relevance for taxation (Section 147(1) nos. 2, 3 and 5 AO).
The auditor is authorised
- to have access to the stored data and to use the data processing system to examine these documents,
- to ask for these data to be evaluated automatically by a computer in accordance with the auditor’s specifications, and
- to request for these to be made available in a machine-readable format (Section 147(6) AO).
The costs incurred in this connection are borne by the taxpayer.
E-mails as documents that are subject to the retention requirement
The BFH, in its rulings of 24.6.2009 (case reference: VIII R 80/06) and of 12.2.2020 (case reference: X R 8/18) had already decided that e-mails should also be included in the trade and business correspondence that is subject to the retention requirement within the meaning of Section 147(1) nos. 2 and 3 AO). The determining criterion is that all the correspondence relating to the business area has to be retained insofar as it refers to the preparation, execution, or reversal of a commercial transaction. The form of communication does not matter here.
According to the BFH ruling, electronic notifications, especially e-mails, are therefore likewise subject to the retention requirement insofar as they contain information that is relevant to financial reporting. If this information is not contained in the text of the e-mail itself, but only in the attachment, then it would be sufficient to retain the attachment (BFH ruling of 12.2.2020, case reference: X R 8/18).
Scope of the auditor’s right to request submittals
Against this background, it is therefore generally permissible if the tax auditor requests that those e-mails be submitted that relate to the preparation, conclusion or execution of a commercial transaction. It is however not permissible for an auditor to ask for the release of all the e-mail communications. The right to request submittals has to be limited to information that is of relevance for taxation.
According to the BFH, a request to prepare a so-called ‘total journal’, which would first have to be created and would include e-mails that are not related to tax, would be explicitly prohibited because there is no legal basis for this. However, if the auditor asks for all the e-mail correspondence that is of relevance for taxation, for example, in connection with incoming and outgoing invoices or a specific issue of relevance for taxation, then the request must be complied with (BFH ruling of 30.4.2025, case reference: XI R 15/23).
Limits of the obligation to cooperate
In practice, a problem that frequently arises is that e-mail data files are not structured in a way that allows tax-relevant messages to be filtered out automatically. It is up to taxpayers, within the framework of their right to initial qualification, to screen out those e-mails that have no relevance for taxation and not to submit them to the auditor. There is however no right to demand that the auditor should restrict their requests to specific search terms, employees or time periods (cf. 200(1) sentence 2 AO).
