Banco Santander (NYSE: SAN) has hired Goldman Sachs (NYSE: GS) and Credit Suisse (NYSE: CS) to explore a potential bid for Citigroup Inc. (NYSE: C) retail bank in Mexico, Grupo Financiero Citibanamex, S. A. de C. V. The move came after Citigroup Inc. announced that it would exit consumer, small business and middle-market banking operations as part of its plan to focus on its consumer banking business. Banco Santander had earlier submitted a non-binding bid for Citibanamex.