The beginning of 2026 did not bring a single, comprehensive tax reform in Poland. Instead, the turn of the year heralded several tax adjustments, while some key measures will become effective over the coming months. For Polish and international businesses operating in the local market, 2026 looks to be less about changes in tax rules themselves and more about adjusting to new compliance requirements, described below.
National e-Invoicing System as a structural shift
The mandatory introduction of the National e-Invoicing System (KSeF) is the most visible symbol of the digital tax transformation. After several postponements, 2026 is the year in which e-invoicing becomes obligatory. From a legal perspective, billing documents cease to function primarily as bilateral documents and instead become structured data records registered in the public systems of the Ministry of Finance.
The phased entry into force is particularly relevant for international groups. Entities whose gross turnover exceeded PLN 200 million in 2024 are required to apply KSeF from February 1 2026, while other VAT-registered taxpayers follow from April 1. For the largest entities, this means that systems must already be operational and fully integrated at the beginning of the year.
An invoice is deemed issued and received at the moment it is assigned a KSeF reference number, eliminating disputes over delivery, duplicates, or document loss. For businesses, this affects payment terms linked to invoice receipt, and enhances the tax authorities’ real-time visibility over commercial flows.
It is also important to note that KSeF generally also applies to cross-border transactions where a Polish taxpayer issues an invoice to a foreign counterparty. While the foreign customer is not required to retrieve the invoice from KSeF and may receive it outside the system, the obligation to issue the invoice within KSeF rests with the Polish supplier. At the same time, mandatory application of KSeF will also affect foreign businesses operating in Poland through a fixed establishment.
Corporate income tax reporting
Running in parallel with KSeF, 2026 also marks a decisive step in the digitalisation of corporate income tax reporting. The obligation to submit accounting books in a structured JPK_CIT format will allow tax authorities to analyse significantly more granular data than before. The scope of reporting covers:
Counterparty data;
KSeF references;
Tax classifications of entries;
Fixed assets; and
Reconciliations between accounting and tax results.
For large taxpayers and capital groups with a tax year aligned with the calendar year, the first reporting cycle is scheduled for March 2026 for the 2025 financial year. Other businesses must ensure compliant data structures from January 1 2026, ahead of reporting in 2027.
A proposal is progressing through the legislative process that would extend the reporting deadline from the end of the third month to the end of the seventh month following the tax year. If adopted, this change could provide additional time to prepare for the first JPK_CIT filings.
(No) withholding tax for dividends paid to investment funds
One of the business-friendly developments effective from January 1 2026 concerns withholding tax on outbound payments. In response to judgments of the Court of Justice of the European Union, Poland is extending the corporate income tax exemption to investment funds and pension funds established outside the EU and the European Economic Area, provided that regulatory comparability conditions are met.
Importantly, the exemption is no longer limited to externally managed funds and now also covers internally managed vehicles operating under appropriate regulatory supervision. From a market perspective, the change may enhance the attractiveness of Polish dividend-paying entities and simplify holding structures for global investors. Given that withholding tax has recently been a heavily scrutinised area in Poland, this reform is a meaningful positive signal for investors.
Procedural rebalancing under in dubio pro tributario
The reinforced in dubio pro tributario principle, effective from the end of 2025, will shape tax disputes throughout 2026. The amended rules require tax authorities to resolve unremovable factual doubts in favour of the taxpayer, extending the scope of the principle beyond purely legal interpretation.
While exceptions remain – notably where an important public interest is invoked – the change should strengthen procedural protection for businesses engaged in complex disputes. In an environment dominated by automated analytics, this safeguard may prove particularly relevant for compliant taxpayers facing challenges triggered by inconsistencies between digital reporting streams.
Pillar two: first reporting and real decisions
Although the global minimum tax rules have already entered into force, 2026 is the year in which they begin to have practical relevance. The first reporting obligations for the initial period will arise for Polish entities belonging to groups with consolidated revenues exceeding €750 million, alongside preparatory decisions that must be taken well in advance of any tax payments.
Particular attention is required where effective tax rates may be reduced by domestic incentives, such as R&D reliefs or special economic zones. While work is ongoing to adjust local incentive regimes to the pillar two framework, no binding solutions have been adopted as yet.
Temporary tax increase for banks
A sector-specific change concerns financial institutions. Under current legislative frameworks, banks will be subject to a temporarily increased corporate income tax rate of 30% in 2026. This measure is designed to be transitional, with a gradual reduction in the tax rate scheduled for subsequent years, accompanied by a parallel decrease in the bank asset tax.
A demanding year even without all planned reforms
Not all planned tax changes have ultimately been implemented. In particular, broader planned changes to income taxes were not enacted, nor were the proposed amendments of rules related to the taxation of Polish family foundations.
Even without these additional reforms, 2026 remains an intensive year for international groups and Polish taxpayers. Since the legislative process is still active, new tax amendments could be introduced at any time. Businesses must follow these developments continuously, as tax changes in Poland are now often implemented on various dates throughout the year.
