An interest calculation mechanism is introduced in the Act on Payment Terms in Commercial Transactions of 8 March 2013 according to which statutory default interest in commercial transactions (i.e. in professional transactions, i.e. between economic operators or between an economic operator and a public entity) shall be calculated at a rate being the sum of the reference interest rate of the National Bank of Poland and 8 percentage points. Consequently, thus calculated rate of interest taking into account today’s reference rate of the NBP equal to 1.5% would be 9.5%. According to the regulations still in force, the rate of default interest in commercial transactions stands at 8%.
 
A mechanism incorporating the reference rate of the NBP in interest calculation has also been added to the Civil Code. Bearing in mind that the Civil Code interest may play the role of the so-called capital interest (Article 359 of the CC) or default interest (Article 481 of the CC) their rate will be different. Therefore, the rate of statutory (capital) interest in non-professional transactions will equal the sum of the reference rate of the NBP increased by 3.5 percentage points. The default rate of interest in non-professional transactions will equal the reference rate of the NBP increased by 5.5 percentage points. Consequently, the rates of interest calculated today would be 5% (capital interest) and 7% (default interest) respectively. Until now, the rate of capital and default interest has been identical, recently standing at 8%.
 
The amendment also introduces the maximum default rate of interest in the Civil Code. The maximum capital interest and the maximum default interest will now be calculated per annum at a level twice as high as the statutory capital interest and the statutory default interest. If the default interest exceeds the maximum default interest the maximum default interest shall be due. Contractual provisions will not be able to exclude or limit the provisions regarding maximum default interest, also if a foreign law has been selected in the contract. The Civil Code provisions on maximum default interest will also apply to commercial transactions, i.e. the maximum rate of interest will not be higher than twice the sum of the reference rate of the NBP and 8 percentage points.
 
The reference rate of interest will be set by the National Bank of Poland. Default interest in commercial transactions will be calculated on the basis of the reference rate of the NBP in force on: (i) 1 January – for interest due for the period between 1 January and 30 June of a given year, (ii) 1 July – for interest due for the period between 1 July and 31 December of a given year.