Is it permissible to collect interest on delayed child support payment?
Answer:
If the interest grows over time, it is not permitted to collect this (from a Jewish father) unless a heter iska is arranged.
Although there is room to permit ribis by way of a kenas (fine) for late payment, this only applies to an amount that is a one-time fine, and not to an amount that grows over time.
Therefore, a heter iska should be arranged.
Best wishes.
