40 P.S §991.2166(b)

(b) If a licensed insurer or a managed care plan fails to remit the payment as provided under subsection (a), interest at ten per centum (10%) per annum shall be added to the amount owed on the clean claim.  Interest shall be calculated beginning the day after the required payment date and ending on the date the claim is paid.  The licensed insurer or managed care plan shall not be required to pay any interest calculated to be less than two ($2) dollars.