Co-founders of US start-up Juul, Adam Bowen (left) and James Monsees. The entreprenurs came up with the idea while pursuing master’s degrees at Stanford University. Photo: AFP
Co-founders of US start-up Juul, Adam Bowen (left) and James Monsees. The entreprenurs came up with the idea while pursuing master’s degrees at Stanford University. Photo: AFP

These entrepreneurs have become the first e-cigarette billionaires