Holds a university degree in business economics. After his studies worked as an accountant for six years including work on mergers and acquisitions. Then Joost worked for an investment company successfully reorganizing a temporary employment agency. Becoming self employed thereafter he was co-shareholder in a medium size publisher/pre press and ad agency. From 1997 he concentrated on merger and acquisition consultancy.
His specialties include human resource services, printing, publishing, ict, telecommunications and wholesale trading.