This file contains the list of VistA Fee Basis invoices that are pending transmission or have already been transmitted to the Fee Payment Processing System (FPPS) hosted at the Health Administration Center (HAC). VistA invoice data must be transmitted to FPPS for invoices that are associated with an electronically submitted health care claim. FPPS can then generate the electronic remittance advice to the vendor as required by HIPAA. Invoices are automatically added to this file when various trigger events occur such as receipt of a payment confirmation message. The interface software uses this file to identify invoices that should be transmitted to FPPS and to maintain a record of transmissions and acknowledgements.