Since August 2026 Türkiye's tax authority has run an electronic audit-preparation system (VDK-İHD), based on the OECD's SAF-T (Standard Audit File for Tax) methodology, already used in 64 countries. For owners of Turkish companies, there is an important practical nuance built into the system: exactly when you receive the letter, and how you respond, can decide whether you pay a penalty at all.
What it is
The Audit Preparation File (İncelemeye Hazırlık Dosyası) is a standardised electronic form through which a company submits requested documents, data and explanations to the tax authority, not as loose paperwork but in a single structured format through a dedicated filing system. It runs on infrastructure that has been in place since October 2025, and was fully launched on 2 August 2026.
The system's first module covers the use of fictitious documents (invoices with no underlying transaction) and is already active. It is planned to extend to other types of audits going forward.
Two different moments the letter can arrive, and why it matters
A letter requesting the file can arrive in two fundamentally different situations, and that changes your entire set of rights.
First scenario: the letter arrives before a formal tax audit has begun. The letter itself is not the start of an audit, it is an information request under the tax authority's general powers. If, while preparing the file, the company identifies and corrects discrepancies itself, and it then turns out that the risks prompting the request no longer exist and there is no indication of a criminal offence, the matter can be closed without ever becoming a full audit. This is precisely the stage where the "voluntary disclosure and correction" protection (Article 371 of the Tax Procedure Law) is available, which waives penalties for voluntarily correcting an irregularity before an audit begins.
Second scenario: the letter arrives from a specific tax inspector as part of an audit already underway. Here the file simply speeds up and standardises a process already in motion, and the voluntary disclosure protection is not available at all: the Article 371 benefit applies only before an audit formally begins.
The takeaway: on receiving the letter, the first task is to establish which of the two regimes it was sent under. That determines whether voluntarily correcting irregularities with penalty protection is still an option, or whether the process is already irreversible.
Data cannot be changed after submission
An important technical feature: once the file is submitted electronically, it cannot be edited. All data, documents and explanations need to be carefully reviewed before submission, rather than relying on the ability to add or correct something later. Information that was forgotten or stated imprecisely can subsequently be presented directly to the examining inspector, but that does not substitute for the original file.
What happens if you do not respond
The audit-preparation letter is formally an information request under the Tax Procedure Law. Receiving it does not, by itself, mean an audit has started or that books must be produced immediately. But failing to respond within the deadline, or providing incomplete or misleading information, triggers a specific procedural penalty under Article mükerrer 355 of the Tax Procedure Law.
Data is not automatically shared with MASAK
Worth noting separately: the preparation-file system is not a reporting mechanism under anti-money-laundering legislation (MASAK). It is a tool specific to the tax authority, and the data is protected under tax-confidentiality rules, used for risk analysis, electronic audit and examinations.
What a company owner should do
If a letter requesting the file arrives, the first action, before filling in the form, is to determine its legal status: was it sent before an audit began, or within one already underway, since that determines whether penalty protection is available at all. Second, bring in both an accountant to gather and verify the data and a tax lawyer to assess the legal consequences, particularly where some information could be unfavourable to the company. Third, remember that nothing can be corrected once the file is submitted, so there is no benefit to rushing, it is better to use the full time allowed for careful review.
Received a letter requesting an audit preparation file, or want to prepare your company for a possible request in advance? We will determine the legal status of the request, gather and verify the documents, and assess whether voluntary-disclosure protection applies in your case. Contact us.