In an old Hong Kong bank vault that has been given a particularly bright lick of paint, some of the smartest young minds from around the world are at a cluster of tables, tapping away on laptops.

In the middle of the room a painting of a unicorn in a kung fu pose recalling Hong Kong's 1970's martial arts star Bruce Lee serves as a reminder of their ultimate ambition - to create Hong Kong's first fintech unicorn, the term for a start-up that has reached a valuation of $1 billion.