Corporate income tax filing software in the Netherlands: what firms check in 2026.

Does the return go via SBR and Digipoort?

Yes. Standard Business Reporting (SBR) is the method for compiling and submitting the return, in the open XBRL standard. All SBR reports to government run through one digital channel: Digipoort. CIT filing software must therefore submit in SBR format; the submitting system needs a PKIoverheid services certificate to send through Digipoort. Check that your package supports the current Belastingdienst taxonomy for the tax year you are filing.

What is the filing deadline in 2026?

In principle the return must be in within five months after the end of the financial year. If the financial year matches the calendar year, the 2025 return is due before 1 June 2026. Extensions are possible: the Belastingdienst usually grants five extra months. If your firm works under the Becon extension scheme (the extension scheme for tax consultants), a longer filing schedule applies under which you file a set percentage of your returns spread across the year. Verify the exact dates and schedule per case; broken financial years and extensions move the deadline.

In practice this means your software has to keep the deadline and extension status visible per client. A missed or misjudged deadline triggers a default penalty, separate from the contents of the return.

What is the role of RGS and the bridge file?

RGS (Referentie Grootboekschema, the Dutch reference chart of accounts) is the standard that links the general ledger accounts in the bookkeeping to the SBR codes you file with. It is the bridge between your own account numbers and the codes you report in to the Belastingdienst, the Chamber of Commerce and the statistics office. A bridge file (brugstaat) is the import file that records that mapping per item, so the annual figures reach the filing software without retyping.

What usually goes wrong is not the technology but the mapping: a mislinked account moves an amount to the wrong line in the return. Good preparation records that mapping deterministically and flags the items the adviser has to review.

What about tax adjustments and the C/F reconciliation?

The return starts from the commercial annual figures, but taxable profit differs from them. Think of an adjustment for fiscal depreciation on a building (capped at the floor value), the deduction limit for mixed costs, the earnings-stripping rule that caps the deduction of net interest, and loss relief. Software has to make that commercial-to-fiscal reconciliation (the C/F reconciliation) traceable, not just show the end figure. In an audit you want to show the bridge from trial balance to taxable profit.

How does the fiscal unity work?

In a corporate income tax fiscal unity the parent company files one combined return for the whole group; the results of the included subsidiaries are taxed at the parent. The requirements are in article 15 of the Dutch Corporate Income Tax Act 1969 (Wet Vpb), including legal and economic ownership of at least 95% of the shares, with at least 95% of the voting rights, the profit and the net assets. Your software must be able to consolidate the group bookkeeping into a single return, including eliminating intercompany positions. The run-up, the formation request itself (Part A and Part B), is separate from the return. Read more about the fiscal unity request.

Where does the client data sit?

For a firm under a duty of confidentiality this is not a detail. A CIT return holds the client's full figures. For every component that touches data (OCR of uploads, storage, processing) check the region and the retention policy. Under the GDPR the firm stays the data controller; a vendor is a processor and should record that in a data processing agreement. Read how we handle data and why everything runs in the EU.