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.
The company provides vehicle tracking, fleet management, data analytics and software services to businesses operating across multiple countries.
Karooooo had a market capitalisation of approximately $1.92 billion (R31.5 billion) in October 2026, valuing Calisto’s reported 58% equity stake at around $1.11 billion (R18.3 billion).
However, his net worth fluctuates with the company’s share price, and estimates have previously placed it between $800 million (R13.1 billion) and $1 billion (R16.4 billion).
Born in Portugal, Calisto lived there for only two years before his parents moved to Mozambique and eventually South Africa. He completed his schooling in South Africa and enrolled at the University of the Witwatersrand to study actuarial science.
He did not complete the degree. In an interview with Forbes, Calisto said he subsequently enrolled at the University of South Africa to study mathematics but left before completing the degree.
After completing his compulsory military service, he entered the workforce through an accelerated training programme offered by Standard Bank between 1986 and 1991.
His career eventually took him into the vehicle-tracking industry, where he worked as a distributor for Netstar.
At Netstar, he helped expand the business into neighbouring African countries and gained experience in a sector that would later become the foundation of his own company.
Calisto attempted to establish Cartrack as a joint venture with Netstar in 2001, but the partnership did not work out.
He subsequently pursued the business independently, with Cartrack operating as an independent company from 2004.
The company began expanding outside of South Africa in 2005, entering Mozambique before broadening its services.
Rapid growth
In 2007, it added fleet management products, helping businesses monitor vehicles, manage operations and improve the use of their fleets.
Three years later, Cartrack developed a software-as-a-service platform, shifting from basic vehicle tracking to a broader technology offering centred on data and business intelligence.
Between 2010 and 2014, it expanded into markets including Spain, Tanzania, Poland, Kenya, Namibia and Portugal, as well as parts of Southeast Asia.
Cartrack was listed on the Johannesburg Stock Exchange (JSE) in 2014, giving investors an opportunity to buy into the growing business.
By 2016, the company had entered the United States and New Zealand, bringing the total to 24 countries.
Cartrack subsequently delisted from the JSE in April 2021 and moved its listing to Nasdaq in the United States under the name Karooooo Ltd, its holding company. At the time, it reported more than 1.5 million active subscribers worldwide.
The group has continued to expand its customer base and recurring subscription revenue. In its second quarter of financial year 2027, ending 31 August 2026, Cartrack’s subscribers increased by 18% year-on-year to 2.9 million.
Karooooo’s total revenue rose 22% to R1.64 billion for the quarter, while operating profit increased 19% to R422 million.
Cartrack subscription revenue grew 20% to R1.42 billion, or 23% when adjusted for currency movements.
Delivery-as-a-Service, the group’s logistics business, also recorded growth, with quarterly revenue increasing 36% to R189 million.
Subscription revenue accounted for 98% of Cartrack’s revenue during the quarter. Calisto said the business continued to see growth, with subscription revenue increasing at a faster rate than in the previous quarter.
Karooooo maintained its full-year 2027 outlook, projecting Cartrack subscription revenue of between R5.7 billion and R6 billion.
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