Bank holding company

A bank holding company, under the laws of the United States, is any entity that directly or indirectly owns, controls or has the power to vote 25% or more of a class of securities of a U.S. bank. Bank holding companies are required to register with the Board of Governors of the Federal Reserve System. Actions of bank holding companies are covered under the Bank Holding Company Act of 1956 ( ).
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Noun
1. a holding company owning or controlling one or more banks
(hypernym) holding company
(hyponym) multibank holding company

A company that owns or has controlling interest  in two or more banks and/or other bank holding companies.