Article 108g of the VAT Act will take effect on 1 January 2027. It obliges the purchaser to state the KSeF number of the invoice or a collective identifier when paying a structured invoice.

The obligation to state the KSeF number of the invoice or a KSeF collective identifier will apply if:

  • the seller and the purchaser are active VAT taxpayers,
  • the payment concerns a structured invoice (including an invoice issued in offline mode but sent to the KSeF system in line with the regulations),
  • the payment instrument allows for stating the KSeF number in the payment reference.

This regulation may also cover the taxpayer that is not the purchaser but makes the payment for the invoice issued to the purchaser (direct debit). For invoices covered by the split payment mechanism, stating the KSeF number of the structured invoice will replace the obligation to state the invoice number in the payment reference.

It is advisable to contact your bank now and determine how to adjust the payment form to enable you to fulfil the statutory obligation. As there are no uniform guidelines, each bank can define its own requirements. The new regulations can have a significant impact on the procedure for paying the liabilities, especially if you have used collective payments or external tools to date.

Collective identifier: a challenge for the accounts receivable process

The collective identifier generated by KSeF will enable fulfilment of the said obligation for a large number of invoices at once (2-10 000 using one identifier). However, the bank will state it in the transaction description only. Thus, the seller should match payments to individual documents ensuring the possibility of linking payments to specific invoices. This may require integration of the KSeF with the accounting system and payment process, and determining the rules of procedure in case of differences between the amount of the payment and the total amount of the invoices in question.

Some transfers do not require the KSeF number

In business practice sometimes it happens that the amount of the transfer is determined based on the structured invoice, but it is not issued to the entity making the transfer. This is the case e.g. when transferring funds received from customers to partners by a platform operator decreased by the commission and paying compensation by the insurer even if its level was established including the invoice documenting the damage repair cost. This approach has also been confirmed by the Director of the National Revenue Information in its recent tax rulings (ref. 0114-KDIP4-3.4012.366.2026.1.DS of 27.07.2026 and ref. 0111-KDIB3-1.4012.306.2026.2.MG of 08.07.2026). Given the diversity of the cases, each process must be verified separately for the obligation of putting the KSeF number in the transfer reference.

Due to the upcoming effective date of the regulation, we recommend reviewing the payment procedures and establishing whether you or your business partners plan to use collective identifiers. This will require adjusting accounting and payment systems, and there may not be enough time for this at the end of the year when other year-end processes are underway.

If this issue pertains to your business and you are interested in our assistance, please contact us.

This blog post is provided for general information purposes to keep you up-to-date with changes in tax law, tax rulings by authorities, case law of courts and interesting commentaries. Doradztwo Podatkowe WTS&SAJA shall not be held legally liable for any acts or omissions resulting from reliance on such information.