Article 60
1. Where an instalment of contributions payable under this Article is not paid by the concerned deadline fixed by paragraphs 2 to 5 of Article 57, the Member State concerned shall be required to pay interest in respect of the unpaid amount. 2. The interest for unpaid amounts shall be charged at a rate of two percentage points above the interest rate applied by the European Central Bank to its main refinancing operations on the first working day of the month in which the amount falls due, as published in the C series of the Official Journal of the European Union . That rate shall be increased by a quarter of a percentage point for each month of delay. The interest shall be payable for the entire period of delay and shall be calculated from the first calendar day following the deadline for payment of the concerned instalment. 3. In respect of the amount due to the Commission under Article 57(7)(a), late payment interest shall be credited to one of the accounts provided for in Article 1(6) of the Internal Agreement. In respect of the amount due to the EIB under Article 57(7)(b), late payment interest shall be credited to the Investment Facility.