Kraïtchik was « agrégé » of the Free University of Brussels, engineer at the “Société Financière de Transports et d'Entreprises Industrielles (Sofina)”, and director of the “Institut des Hautes Etudes de Belgique”.
He is a member of the board of directors of the Groupe Danone and Sofina, director and member of the audit committee of the Delhaize Group, and SES.
In the mid-1950s, Mediobanca entered into agreements with important foreign partners (Lazard Group, Berliner Händel-Gesellschaft, Lehman Brothers, Sofina) that enabled the bank to play a role on the international market and obtained a Stock Exchange listing in 1956.