Has management experience that spans more than 30 years, leading financial institutions that include the Citibank/Citicorp (Manila & New York); Bank of the Philippine Islands; Monte de Piedad Savings Bank; First Metro Investment Corporation; Global Business Bank; and the Equitable-PCI Bank. He was also at the helm of the Philippine Central Depository, Inc.; the Securities Clearing Corporation of the Philippines; and the Philippine Stock Exchange, Inc. He also served as Director for Philex Mining Corporation; Manila Electric Company; and San Miguel Corporation, concurrently when he was Chairman and Administrator of the Social Security System. He was also a Director of the North Luzon Railways Corporation.

At present, he is the Chairman and President of Organizational Systems, Inc. and AMVI Development Corporation; President of CODIS Federation of Cooperatives; Director of the National Cooperative Mutual Fund of the Philippines; Director of Terelay Investment and Development Corp.; Trustee of International Center for Innovation, Transformation and Excellence in Governance (INCITEGov); Director of The Pioneer Group of Companies; and Financial Consultant of Pag-asa Steel Works, Inc.; Diamond Auto Group; among other business concerns.

Aside from being a financial and management consultant for various Philippine and multinational companies, Mr. Nañagas is also active in civic and professional activities in such noted organizations as the Pondo ng Pinoy; Philippine Agrarian Reform Foundation for National Development (PARFUND); Christian Life Community of the Philippines; Roman Catholic Archdiocese of Manila (RCAM); Ramon Magsaysay Award Foundation; the Management Association of the Philippines; Asian Social Institute, Inc.; PinoyME Foundation; Philippine Council for NGO Certification (PCNC); Foundation for Economic Freedom; Foundation for the Philippine Environment and Cartwheel Foundation. Currently, he is also the Chair of Bahaginan Foundation; Founding Member of the VSO Federation Council; Vice Chair of NORFIL Foundation; Finance Com member of the Peace and Equity Foundation, and is the Finance Committee Chair of the Assumption College.

In August 1997, he was conferred the Papal Award (Knight of the Pontifical Order of St. Sylvester) by Jaime Cardinal L. Sin.