The youngest billionaires in the world in 2018

 Gustav Magnar Witzøe owns almost half of Norwegian fish farming company Salmar, which is one of the world’s largest salmon producers.
His father, Gustav Witzøe — who still runs the company — gifted this stake to him in 2013.

3. Gustav Magnar Witzøe, 24 — $1.9 billion (£1.4 billion).