As marketing departments in companies across various industry sectors, such as banking, insurance, and financial services, continue to grow in strategic importance, they have begun to recognize the crucial role that data plays in their success. They feel the intense market pressures to find effective ways to cross-sell and up-sell to new and existing customers in order to improve response rates, and increase revenue. The purpose of this article is to illustrate two tree-based approaches of CRM Cross-Selling and Up-Selling. One is a statistics based paradigm using “if-then” rules, like CHAID, and the other is a machine learning based paradigm using genetic analysis and modeling, like The GenIQ Model©. I demonstrate the two approaches with cased studies from the financial services sector.