 NEW YORK--BUSINESS WIRE--Ambac Financial Group, Inc. NYSE: AMBC, a financial services holding company, today announced that its subsidiary, Ambac Assurance Corporation AAC executed a plan support agreement the PRIFA PSA that provides for a consensual settlement of its insured exposure to bonds issued by the Puerto Rico Infrastructure Financing Authority PRIFA. AAC today also joined a plan support agreement the GOPBA PSA related to general obligation GO bonds issued by t 