In a previous newsletter, we explained how to protect your business during an unannounced visit from the tax authorities. This time, we take a closer look at one aspect of these inspections that is becoming increasingly common: your email inbox.
Invoices, the general ledger and purchase orders: no one is surprised when a tax inspector wants to examine them. Increasingly, however, the tax authorities are also requesting access to the entire business email inbox. During tax audits, an employee from the e-audit department often accompanies the inspectors to download the contents of the mailbox covering the full statutory retention period of seven years.
Such a request can be quite unsettling. After all, an email inbox often contains much more than documents relevant to tax matters: correspondence with your lawyer and accountant, private messages, emails concerning other companies and sensitive client information. What are the tax authorities allowed to do, and how can you best prepare?
What are the tax authorities allowed to do?
Businesses that keep their accounts digitally must also provide the tax authorities with access to their digital records upon request (Article 315bis of the Belgian Income Tax Code 1992 and Article 61 of the Belgian VAT Code). On 24 June 2025, the Ghent Court of Appeal confirmed that this also applies to an email inbox used for professional purposes.
This does not mean that the tax authorities can simply take whatever they want. Copies must be made by the company itself, using its own equipment and in the presence of the inspectors. If the company objects, the tax authorities cannot enforce the request on their own authority. This was already established in a ruling of 15 March 2022. In that case, the tax authorities had copied a company's entire email inbox without its consent. The court ruled that the evidence obtained from that copy had been unlawfully acquired and excluded it. If the tax authorities still want access, they must apply to the court. The court may order the mailbox to be copied and sealed pending a ruling. This also happened in the case that led to the 2025 judgment.
Correspondence covered by professional confidentiality must also be separated beforehand. The court confirmed that this applies not only to correspondence with your lawyer, but also to correspondence with your accountant. Whether such correspondence is actually protected is determined not by the tax authorities, but by the competent professional disciplinary body. However, there is an important point to bear in mind: in its 2025 judgment, the court did not accept that a company could decide for itself which emails were relevant for tax purposes. If you mix business emails, private messages and correspondence relating to other companies in a single inbox, it will be difficult to use this as an argument to restrict access later on.
Seven years back? Not without good reason
The tax authorities often refer to the statutory retention period when requesting access to seven years of emails. However, the retention period is not the same as the period during which the tax authorities can still assess tax. In principle, this period is three years. A longer period is only possible where there are indications of fraud.
If an inspector wants to go further back, they must therefore explain which specific indications justify applying the extended period. For income tax purposes, the tax authorities must even communicate these indications precisely and in writing beforehand, specifying the tax assessment years concerned. Without this notification, the investigation for those years is invalid, and there is no reason to provide documents relating to years for which adjustments can no longer be made. In the 2025 judgment, the tax authorities were even required to return data dating from before the investigation period. However, they may specifically request older documents that still have an impact on more recent years, such as an ongoing contract. General access to all older data is not permitted.
How to prepare your email inbox for a tax audit
One company, one email inbox. Do you operate several companies, such as an operating company, a management company, a property company or a foreign entity? Use a separate email address with its own domain extension for each company. A tax audit concerns a specific taxpayer. If you keep everything in one inbox, you allow the inspector to access files that fall outside the scope of the audit.
Keep private matters private. Your business email inbox (and business messaging apps such as Teams or a business WhatsApp account) is not the place for family messages, holiday bookings, medical appointments or personal purchases. Use a private email address and a personal device for these.
Keep confidential correspondence separate. Correspondence with your lawyer and accountant is covered by professional confidentiality and must be filtered out in any case. Correspondence with your bank is not protected by professional confidentiality, but it is best kept separate as well. Make this practical by creating clearly labelled folders ("Confidential: lawyer", "Confidential: accountant", "Confidential: bank") and setting up automatic rules so that emails from these senders are immediately filed in the appropriate folder.
Organise emails by project or file. Store quotations, purchase orders, plans, additional work agreements and invoices for each project in a consistent folder structure. When an inspector requests a specific document, you can respond with the relevant information. This is far more efficient than getting into a discussion about downloading your entire inbox.
Make sure quotations, purchase orders and invoices are consistent. Many tax disputes arise because emails tell a different story from the invoices. Has the rate or description of the work changed? Make sure the reason is documented in writing.
Write as if the tax authorities were reading your emails. A business email can serve as evidence. Be professional, accurate and thorough. Casual remarks or informal agreements about prices, discounts or payments are often read later without the original context.
Establish an email policy and apply it consistently. Set out in writing how long business emails are retained within the company, when mailboxes are cleaned up and who has access to which inbox. These rules apply not only to company directors, but to all employees. Make sure your staff are clearly informed. Then regularly clean up mailboxes in accordance with this policy, regardless of whether an audit is taking place.
Deleted emails are rarely gone for good.
- They first go to the trash folder and can often still be recovered for several weeks.
- Additional archiving features are often in place, and email traffic may also be stored at network level, independently of your laptop.
- Every deletion is logged, and a download can reveal which emails were deleted and when.
The tax inspector requests access to your inbox. What now?
Cooperate, but within the scope of the audit. Do not allow a complete download of your inbox. Instead, ask which invoices, projects or periods the inspector specifically wants to examine. You can then provide the relevant correspondence. If the inspector requests documents dating back more than three years, ask on what grounds. Make sure your position is recorded in the audit report and confirm it in writing. Contact your tax lawyer as soon as possible.
Facing a tax (e-)audit?
Have you received notice of an upcoming tax audit or e-audit? Contact our team. We will be happy to review with you which documents must be provided and which do not need to be disclosed.
