A Warsaw-based technology company receives a formal notice from the Krajowa Administracja Skarbowa (National Revenue Administration, KAS) announcing the opening of a tax audit. The letter arrives on a Tuesday morning. By Thursday, the company's management has still not contacted a tax advisor, has not secured its documentation, and has not identified which fiscal year is under scrutiny. That delay – measured in days, not months – can cost the company its strongest procedural defences.

A KAS tax audit in Poland is a formal administrative procedure conducted by the National Revenue Administration to verify whether a taxpayer has correctly calculated and paid its tax obligations. The audit is governed by Polish tax procedural law and may cover any tax type – VAT, corporate income tax (CIT), transfer pricing, or payroll levies – for up to five years back from the end of the calendar year in which the tax liability arose. Failing to respond correctly within the statutory deadlines precludes key rights, including the right to submit voluntary corrections that reduce penalties.

This guide walks through the full KAS audit cycle: how an audit begins, what KAS investigators actually examine, where companies make avoidable errors, and how three distinct business profiles – a domestic manufacturer, an IT firm using the IP Box regime, and a foreign investor with a Polish subsidiary – should each approach the process differently. A practical checklist and FAQ section close the guide.

How does a KAS tax audit begin – and what triggers one?

KAS selects audit targets through a combination of automated risk-scoring and sector-specific campaigns. The National Court Register (KRS) filings, JPK_VAT data submitted monthly, and cross-border transaction reports all feed into the scoring model. A taxpayer showing a persistent VAT refund position, unusually high intra-group costs, or IP Box deductions without corresponding R&D documentation will score higher. Scoring alone does not guarantee an audit, but it narrows the pool considerably.

The formal audit opens with a written authorisation notice (upoważnienie do przeprowadzenia kontroli podatkowej). This document names the auditing officers, defines the scope – which tax, which period – and sets the clock running. From that moment, the taxpayer generally has seven days before investigators may appear at the premises. That seven-day window is the single most valuable preparation period in the entire procedure.

Three situations trigger heightened KAS attention:

  • Transfer pricing adjustments that reduce taxable income by more than PLN 500,000 in a single year
  • VAT refunds claimed within 25 days under the accelerated procedure
  • IP Box deductions where the R&D activity register (ewidencja) was not maintained from the first day of the tax year

A separate, more intrusive instrument is the kontrola celno-skarbowa (customs and fiscal audit, KCS). Unlike a standard tax audit, a KCS may begin without advance notice. It is used in fraud-suspected cases and carries a longer investigation horizon. Companies receiving a KCS notice rather than a standard audit authorisation should contact a tax advisor within 24 hours – not 24 days.

One practical point worth flagging: the Polish Financial Supervision Authority (KNF) and the General Inspector of Financial Information (GIIF) may share intelligence with KAS in cases involving suspicious financial flows. Foreign investors with Polish subsidiaries should therefore treat AML compliance and tax compliance as linked, not parallel, workstreams.

What does KAS actually examine during the audit?

The scope of examination is defined by the authorisation notice, but KAS officers have broad discretion within that scope. They may request any document, electronic record, or correspondence that relates to the declared tax position. In practice, the first request typically covers three categories: accounting books, source invoices for the five largest cost items, and any agreements with related parties.

For VAT audits, investigators compare JPK_VAT files against the company's purchase and sales registers. Discrepancies of even PLN 10,000 will generate a formal query. Since the introduction of structured e-invoicing under KSeF – Poland's National e-Invoice System – KAS has access to invoice-level data in near real time. Companies that have already onboarded to KSeF find that auditors arrive with pre-prepared transaction maps. That transparency cuts both ways: clean data accelerates closure, while inconsistencies are immediately visible.

Transfer pricing documentation receives separate treatment. KAS officers will examine whether the master file and local file were prepared on time, whether benchmarking studies reflect arm's-length conditions, and whether any year-end transfer pricing adjustments were correctly reported. A local file prepared after the audit notice arrives carries no evidentiary weight. The documentation must pre-date the audit by the statutory deadline – generally the date of filing the annual CIT return.

We secured a reversal of a VAT surcharge exceeding PLN 1.8m for a manufacturing client in the Mazowieckie region (autumn 2025). The authority had disallowed input VAT on the grounds that the supplier chain included a missing trader. Our team demonstrated through contemporaneous delivery records and payment confirmations that the client had exercised due diligence. The case closed without penalty.

IP Box claims attract particular scrutiny. The Polish tax law allows a 5% preferential CIT rate on income derived from qualifying intellectual property rights, but only where the taxpayer maintains a granular activity register from the first day of the year. KAS officers will check whether hours, costs, and outcomes are recorded at the project level. A consolidated annual summary does not satisfy the requirement.

Where do companies make the most costly mistakes?

The most expensive errors are procedural, not substantive. A company with a defensible tax position can still face surcharges and penalties if it mishandles the audit process itself. Three patterns repeat across industries.

First, companies fail to designate a single point of contact for KAS correspondence. When different employees respond to different requests, inconsistencies appear. KAS officers are trained to identify contradictions between responses submitted on different dates. Designating one senior finance officer – supported by external counsel – to manage all communications eliminates this risk.

Second, companies submit documents voluntarily that fall outside the audit scope. An auditor asks for invoices from Q1; the company sends the full year. That expanded dataset becomes part of the audit record. Polish tax procedural law does not require a taxpayer to produce documents beyond the defined scope. Producing them without legal review is a common and avoidable error.

Third, companies miss the 14-day deadline to submit written explanations in response to a formal query (wezwanie). Missing that deadline does not close the case – but it eliminates the taxpayer's ability to shape the evidentiary record before the officer drafts preliminary findings. Preliminary findings, once issued, are very difficult to reverse at the administrative level.

For companies operating in corporate groups, a related risk arises from subsidiary liability. Where a parent company's pricing decisions affect the Polish subsidiary's tax base, the subsidiary may bear the audit consequences even though the pricing policy originated abroad. Understanding the interaction between group-level decisions and Polish tax exposure is addressed in more detail in our analysis of subsidiary liability in Polish corporate groups.

How should three different business profiles approach a KAS audit?

Audit preparation is not one-size-fits-all. The risk profile, documentation burden, and optimal response strategy differ significantly depending on the company's activity, ownership structure, and tax history.

Domestic manufacturer. A Polish manufacturing company with revenues above PLN 50m is likely subject to transfer pricing documentation requirements if it purchases raw materials from a related supplier. The audit focus will be on whether the pricing of intra-group purchases is arm's-length. Preparation should begin six months before the CIT filing deadline: commission a benchmarking study, document the supply chain rationale, and ensure that any year-end TP adjustment is reflected in both the CIT return and the JPK_CIT file.

IT company using IP Box. An IT firm claiming the 5% IP Box rate must demonstrate that its qualifying IP – typically software – was created through R&D activity conducted by the company itself. The activity register must show individual projects, the employees or contractors involved, time allocation, and the nexus between that activity and the qualifying income. A company that began maintaining the register only from the second quarter of the tax year will face a partial disallowance. Estimated exposure: the difference between the standard 19% CIT rate and the 5% IP Box rate, applied to the full year's qualifying income, plus a 50% surcharge on the disallowed amount.

Foreign investor with Polish subsidiary. A German investor whose Polish subsidiary provides shared services to the group faces two simultaneous risks: transfer pricing exposure on the service fee, and permanent establishment risk if group managers exercise control over the Polish entity from abroad. KAS has increased its scrutiny of service fee arrangements since 2023. Foreign investors should review management agreements, ensure that the Polish subsidiary's board exercises genuine decision-making authority, and document the substance of local operations. Our analysis of what KSeF means for cross-border invoicing structures – including the implications for Swedish-Polish trade flows – is covered in our piece on what KSeF means for your business in Sweden.

We obtained a successful outcome for a German-owned IT subsidiary in Lower Silesia (spring 2026), where KAS had proposed a PLN 3.2m upward adjustment to the subsidiary's taxable income on the basis that the service fee paid to the German parent exceeded the arm's-length range. Our team reconstructed the benchmarking analysis using updated comparables and submitted a revised local file within the statutory response period. The proposed adjustment was withdrawn in full.

What should you prepare before and during the audit?

Preparation falls into two phases: pre-audit readiness (ongoing) and immediate response (the seven-day window after the authorisation notice arrives). Both phases require coordinated action between the finance function, management, and external tax counsel.

Pre-audit readiness means maintaining documentation in a state that can withstand scrutiny at any time. That includes keeping transfer pricing files current, maintaining IP Box activity registers from January 1 of each year, reconciling JPK_VAT data monthly against the accounting system, and documenting the business rationale for any transaction that reduces taxable income by more than PLN 200,000.

Immediate-response checklist – what to prepare in the seven-day window:

  • Identify the precise scope of the audit (tax type, period, named officers) and circulate internally
  • Designate a single point of contact for all KAS correspondence and brief that person on document-handling rules
  • Secure and organise source documents for the audited period – invoices, contracts, bank statements, and correspondence
  • Commission an internal pre-audit review of the key positions under scrutiny, with a written legal opinion
  • Confirm that transfer pricing documentation and IP Box registers pre-date the audit notice

During the audit itself, every document submitted to KAS should be logged with a date, a description, and the name of the officer who received it. Oral statements should be avoided where possible; where an officer requests an explanation verbally, follow up in writing within 48 hours to create a paper record. The audit closes with a post-audit protocol (protokół kontroli). The taxpayer has 14 days from receipt of the protocol to submit objections. That objection window is the last opportunity to correct the factual record before the authority issues a decision.

A family foundation holding Polish operating companies should note that KAS has begun examining distributions from foundations to beneficiaries to verify whether the underlying assets were correctly valued at the time of contribution. This is an emerging audit focus, distinct from the standard corporate tax audit cycle.

Frequently asked questions

Q: How long does a KAS tax audit typically take?

A: A standard tax audit (kontrola podatkowa) should be completed within three months of the opening date, though extensions are possible in complex cases. A customs and fiscal audit (kontrola celno-skarbowa) may run for up to three months initially, with extensions possible up to six months in total. In practice, transfer pricing and VAT fraud investigations frequently exceed these limits through procedural extensions. Building in a realistic timeline of six to nine months for a complex audit is prudent.

Q: Can a company correct its tax return after a KAS audit has started?

A: This is a common misconception. Polish tax procedural law suspends the right to submit a voluntary correction once a tax audit has formally opened for the period and tax type under examination. The right to correct is restored only if the audit closes without a decision being issued. This is precisely why pre-audit compliance reviews matter: a voluntary correction filed before the audit notice arrives attracts a reduced penalty rate of 10%, compared to the standard 50% or 75% surcharge applied after an audit finding.

Q: What does a KAS audit cost the company in professional fees?

A: Professional fees for external tax counsel during a KAS audit typically range from PLN 30,000 to PLN 150,000 for a mid-market company, depending on the complexity of the issues, the number of tax years under review, and whether the case proceeds to administrative appeal. Transfer pricing audits and IP Box reviews tend to fall at the higher end of that range. The cost of professional representation is almost always lower than the cost of an uncontested audit finding – which may include the unpaid tax, a surcharge of 50–150%, and interest accruing at the statutory rate.

KORDECKI & Partners is a law firm based in Warsaw and Krakow, advising business clients across 30 jurisdictions. Our team combines expertise in Polish and international law with a practical approach to tax audit defence, KAS proceedings, transfer pricing, and tax-court litigation before the Provincial Administrative Court (WSA) and the Supreme Administrative Court (NSA). We work with Polish entrepreneurs, foreign investors, and in-house legal teams. To discuss your situation, contact info@kordeckipartners.com.

A specific audit notice – or an awareness that your company's documentation does not yet meet the standard KAS will apply – requires immediate, tailored action. Waiting until the auditors arrive forfeits the most valuable procedural protections available under Polish tax law.

If your company is facing a KAS audit notice, preparing for an upcoming compliance review, or restructuring its transfer pricing or IP Box documentation – our team will conduct a rapid pre-audit assessment, identify exposure, and build your response strategy: info@kordeckipartners.com.

Disclaimer: This publication is provided for informational purposes only and does not constitute legal advice. The information herein should not be relied upon as a substitute for professional legal counsel tailored to your specific circumstances. KORDECKI & Partners assumes no liability for actions taken or not taken based on the contents of this material. For advice regarding your particular situation, please contact info@kordeckipartners.com.