Both sons were educated in the United States, at Harvard University and MIT, respectively. Walter Kohl worked as a financial analyst with Morgan Stanley in New York City and later founded a consulting firm with his father in 1999. Peter Kohl worked as an investment banker in London for many years. Walter Kohl was formerly married to the business administration academic Christine Volkmann and they have a son, Johannes Volkmann; he is now married to the Korean-born Kyung-Sook Kohl née Hwang. Peter Kohl is married to the Turkish-born investment banker Elif Sözen-Kohl, the daughter of a wealthy Turkish industrialist, and they have a daughter, Leyla Kohl (born 2002).