 NEW YORK--BUSINESS WIRE--Ambac Financial Group, Inc. NYSE: AMBC, a financial services holding company, today announced that it has rescheduled the release of its first quarter 2021 results to May 10, 2021, before market open. Ambac is rescheduling the release to allow it to consider the possible effect on first quarter results of the May 5th announcement by the Financial Oversight and Management Board FOMB for Puerto Rico. The FOMBs announcement provides details on an agreement with ce 