“We have to file D406.” If that sentence has recently come up in conversations with your accountant, and your answer was an uncertain “right…”, this article is for you. It is not an accounting guide — it is an explanation, in business-owner language, of what SAF-T actually demands from your IT systems.
Because this is what often gets lost in the discussion: D406 looks like an accounting obligation, but its success or failure plays out in your business software. The return is not “filled in” — it is generated, automatically, from the data your ERP has (or does not have). If the data is clean, filing is a routine. If not, every deadline becomes a rescue operation.
What SAF-T is and what D406 is
SAF-T (Standard Audit File for Tax) is the standard tax audit file: an electronic format through which companies periodically send ANAF (the Romanian tax authority) a detailed X-ray of their accounting and tax records. In Romania, it takes the form of the D406 return — an XML file with a prescribed structure, generated from the accounting data and filed electronically.
The frequency follows your VAT period: monthly for monthly VAT payers, quarterly for quarterly ones. In other words, it is not an annual return you can settle in one week of concentrated effort — it is a permanent flow, which assumes the data is in order all the time, not just at year end.
Why the obligation has reached small companies too
SAF-T was introduced in stages: large taxpayers first, then medium, then small. The staging was designed precisely because adapting systems takes time — and the process is now complete: the obligation covers all categories of taxpayer. Small companies, which had the most time available, are also the ones that often arrived at the deadline the least prepared — not out of bad faith, but because nobody inside had the subject in their job description.
If your company is just starting out with D406, the good news is that the path is already well trodden: the typical mistakes are known, and Romanian accounting and business management software has had years to build its exports. What remains is your part: checking that the chain works end to end at your company, not just in the vendor's brochure.
What data goes into D406
Without going into the technical structure of the file, the return takes information directly from the accounting records: identification data and master lists (customers, suppliers, accounts, products), the accounting journals, sales and purchase invoices, payments and receipts. Certain sections — for example those relating to stocks or assets — have their own rules and deadlines; there, let your accountant lead the discussion and ask for the exact list of what applies to your company.
The important point for you is a different one: all this data must exist in the system, complete and consistent. The XML file is merely its mirror.
The part that belongs to IT: can your software generate the file?
This is where the paths diverge. The question is not just “does the software have a D406 export button?” — most do. The question is whether the data behind the button is in the required state. The problems that come up most often:
- Partners with incomplete data: customers and suppliers without a valid tax ID, with duplicate names or a missing country. Every limping record can become a validation error.
- The chart of accounts: the structure the return requires assumes a clear mapping between the accounts the company uses and the prescribed nomenclature — if the company uses exotic analytical accounts, the mapping must be defined explicitly.
- Product lists and VAT rates: items created in a hurry, rates assigned manually, inconsistent units of measure — they all surface at export.
- The history: old data, migrated at some point from a previous system, can have gaps that never bothered anyone until now.
The practical rule: generate a test file early and run it through the validator made available by ANAF before the first real deadline. The error list from the first test is, in fact, your work list — and it is far more pleasant to discover it on a quiet day than on filing day. If the errors turn out to be structural — data that needs cleaning in bulk, exports that need building or completing — that is where a focused development and automation project becomes useful, one that fixes the cause, not just the symptom at every deadline.
The questions to ask your software vendor
- Does the D406 export cover all the sections that apply to our company, at our reporting frequency?
- What happens when the structure required by ANAF changes — does the update arrive automatically, on time, and at what cost?
- Is there a validation before export that shows us the data errors directly in the program, not only at filing?
- How is a return that has already been filed corrected, and how hard is it to rebuild the file?
- Who answers questions in the week of the deadline — and how quickly?
Vague answers to questions 2 and 5 are the classic warning sign: the obligation is periodic, so the support must be too.
Who files: the accountant, the software or both
In practice, D406 is a team sport: the accountant is responsible for the correctness of the data and for filing, the software for generating the file, and the company — that is, you — for making sure the two have what they need. Most blockages appear exactly at the boundaries: the external accountant has no access to the ERP, the ERP exports in a format the accountant's program cannot read, nobody knows who presses the button during the holiday week.
It is worth a one-hour discussion, once, in which you establish: who generates the file, who validates it, who files it, who keeps the evidence and how data moves between systems without repeated manual exports. If you do not know who to have that discussion with on the technical side, the frequently asked questions about IT consulting show how such clarifications are usually approached.
And one more thing: D406 is not the only digital obligation with a deadline in 2026 — the e-Factura rules changed too on 1 January, and the two rely on the same data and the same systems. A clean-up done once serves them both.
The next step: ask your accountant for the date of the company's first (or next) D406 deadline and schedule a test export at least a few weeks in advance. Neoxis, an IT services company founded in 2015 in Pitești, works with SMEs across Romania on exactly this kind of system preparation.