The concept of a FE itself has not changed. It has long been part of the VAT system and has been extensively addressed in the European case law. What has changed is the practical relevance of FE in the KSeF environment. The latest tax authorities’ explanatory notes (issued on January 28^th) introduce certain legal assumptions as to whether the seller may assume the invoice exchange via KSeF to be sufficient (i.e. no separate e-mails/PDF’s needed).

According to the explanatory notes, a Polish supplier is not required to carry out an in-depth assessment of whether a foreign customer actually has a FE in Poland in a substantive VAT sense. For the purposes of determining the correct invoicing method, the supplier may rely on formal and objectively verifiable criteria.

In this context, particular importance is attached to the use of a Polish VAT identification number by the foreign buyer. The mere allocation of a Polish VAT number does not, in itself, determine the existence of a FE. However, where a foreign counterparty (i) uses a Polish VAT number in a specific transaction yet (ii) does not provide the supplier with a statement confirming the lack of a Polish FE involved in that transaction, the Polish supplier may assume that such FE exists and is involved. As a result, the invoice may be issued exclusively via KSeF, with no obligation on the seller’s side to make it available to the buyer outside the system.

This presumption is procedural in nature and is intended to protect the Polish supplier when selecting the appropriate invoicing model. It does not determine whether a FE actually, nor does it conclusively qualify the foreign entity’s structure for VAT purposes. Nevertheless, the absence of a statement from the foreign B2B-buyer operates to its disadvantage, regardless of whether its presence in Poland is operational or purely auxiliary.

The explanatory notes further clarify that the mere existence of an office, branch or administrative facilities in Poland does not automatically give rise to a FE, provided that such structures do not actually participate in the supply of goods or the provision of services. The autonomous nature of the FE concept also means that the existence of a “permanent establishment” for corporate income tax purposes, or capital links with Polish entities, is not decisive for VAT purposes.

From the perspective of Polish suppliers, this approach increases legal certainty and stabilises invoicing processes by removing the need for a detailed, case-by-case verification of the foreign counterparty’s status. However, for foreign entities holding and using a Polish VAT number, it means that information relating to the existence or non-existence of a fixed establishment must be actively managed in relations with Polish suppliers. The absence of appropriate procedures and failure to submit no-FE statements may result in invoices being issued solely through KSeF.

In this sense, the explanatory notes give the concept of a fixed establishment a distinctly practical dimension. In the KSeF environment, using a Polish VAT number without an appropriate statement may result in a transaction being brought within the KSeF regime, regardless of the foreign entity’s actual operating model.

In practice, this requires foreign companies to consciously manage the risks associated with having a potential fixed establishment in Poland and to align their internal procedures with the requirements of KSeF. This includes, in particular, reviewing the operating model from an FE perspective, preparing and using no-FE statements or statements confirming the lack of FE involvement in specific transactions, and properly structuring invoicing rules and communication with Polish counterparties. In the worst-case-scenario, they might lose access to their Polish purchase invoices, which in turn could cause issues with crucial payments (e.g. energy).