Polish Businesses Face Potential double Taxation Under New KSeF Invoice Rules
WARSAW, Poland – A looming regulatory ambiguity surrounding Poland’s National System of Electronic Invoices (KSeF) threatens to force businesses to issue-and possibly pay taxes on-the same sale twice beginning in February 2026, according to leading fiscal expert Prof. witold Modzelewski of the Institute of Fiscal Studies. The concern stems from unclear stipulations regarding invoice formats and the potential for KSeF to trigger the creation of multiple, legally valid invoices for a single transaction.
The core of the issue lies in the VAT Act’s definition of acceptable invoice forms-paper, electronic, and structured-and how these interact with KSeF requirements.While KSeF mandates structured electronic invoices conforming to a specific template, businesses are already signaling intent to supplement these with additional commercial data, potentially creating a divergence from the legally prescribed format. Currently, this isn’t a major concern, but the introduction of KSeF fundamentally alters the landscape.
According to Article 106nda, 106nf, and 106nh of the VAT Act, electronic invoices must adhere to the structured invoice template, a requirement whose rationale remains unexplained. Prof. Modzelewski warns that if a business issues a structured electronic invoice through KSeF and simultaneously generates a separate invoice-even a paper one-to include additional business details, both documents could be considered legally valid “invoices,” triggering a double tax liability.
“The basic problem is therefore the statutory form of the invoice: in accordance with Art. 2 of the VAT Act, ther are only three separate forms of VAT invoices: paper, electronic and structured,” Prof. Modzelewski stated. “Though, by reading subsequent regulations on this subject, you may come to the conclusion that a given activity may require the issuance of an invoice in two or even three forms and each of them is an ‘invoice’ in the legal sense.”
ksef, designed to streamline VAT reporting and combat tax evasion, is scheduled to become mandatory for most Polish taxpayers starting February 2026. The system requires all invoices to be submitted electronically, but the lack of clarity regarding acceptable invoice formats and the potential for multiple valid documents raises important concerns about compliance and financial risk for businesses. The question remains: will authorities clarify the regulations, or will polish companies be forced to navigate a complex and potentially costly double-invoicing scenario?
