G uillaume Pousaz is a Swiss self-made billionaire and the founder and CEO of Checkout.com, a global online payments platform that has become one of the most valuable private fintech companies in the world. A university dropout, Pousaz founded the company in 2012 with the vision of creating a more modern and flexible payment processing solution for international e-commerce businesses.

He bootstrapped the company for many years, focusing on building a robust, unified platform that could handle payments in multiple currencies and methods. The company's technology-first approach and its ability to serve large, fast-growing digital businesses attracted a blue-chip client list. In 2019, after years of operating under the radar, the company announced a record-breaking Series A funding round that revealed its massive scale and profitability. Subsequent funding rounds have pushed its valuation into the tens of billions, making Pousaz one of the wealthiest entrepreneurs in Europe. He is known for being very private.