According to the agency, the date of tax liability is determined as the earliest of the following three dates:
- the date specified in the invoice as the delivery date;
- the date when the cash register receipt was issued;
- the date of payment receipt.
It is important to note that if an entrepreneur receives an advance payment, it is immediately included in the taxable base in the reporting period when the funds were actually received, even if the goods have not yet been shipped and the services have not been rendered.
The STS also reminded that the taxable object for sales tax includes goods, works, or services that are paid for both in cash and non-cash. Thus, advance payments must be accounted for in the reporting at the time they are received.
Therefore, in reports for the single tax and sales tax, all receipts for the reporting period, including advance payments, should be summed up in the lines where revenue volume is indicated.
Taxpayers are urged to take the new rules into account when preparing reports for 2026.
