Two Brisbane entrepreneurs whose start-up helps major companies find weaknesses in their cybersecurity have sold out to a British private equity-backed firm for more than $100 million.

Michael Gianarakis and Shubham Shah, who describe themselves as ethical hackers, founded Assetnote in 2018. They have since signed Atlassian, Qantas and Canva as clients, and have been profitable since they started. That has allowed them to keep big ownership stakes in the business as it grew.