ISO New England assesses an interest charge for invoices paid after the due date. The interest charge is based on the FERC prime rate for the number of days outstanding. A late fee may also be assessed—see the Late Fees page.
The provisions of interest charges are found in the ISO New England Billing Policy.
Any market participant who pays their invoice after the due date can expect to see an interest charge on the next monthly bill.
Interest charges are included on the monthly bill. The line item is entitled “Interest Charges.”