The South African who dropped out of university, joined the military, and then became a billionaire

Isaias (Zak) Calisto dropped out of university twice and completed compulsory military service before building a technology company that has made him a billionaire.Calisto is the founder and chief executive of Karooooo Ltd, the Singapore-headquartered company behind Cartrack, one of South Africa’s largest fleet management and vehicle telematics businesses.