Humer is chairman of Roche Holding while Spero is a senior research scholar at Columbia University School of International Public Affairs.
Citi board of directors chairman Richard Parsons said both candidates will bring considerable insight to the Board as the firm continues to grow internationally and build on its unmatched global strengths.
Humer has worked as chief executive officer of the Roche Group from 1998 until 2008 and prior to this, he served as chief operating officer and head of pharmaceuticals for F Hoffmann-La Roche.
Spero served as the president of the Doris Duke Charitable Foundation and to this she was the under secretary of State for Economics, Business and Agricultural Affairs.
Citi runs banking business across 160 countries, serving nearly 200 million customers by providing a broad range of financial products and services, such as consumer banking and credit, corporate and investment banking, securities brokerage, transaction services and wealth management.
