Twenty-year-old Alexandra Andresen from Norway is the world's youngest billionaire with a net worth of $1.2 billion, according to Forbes Billionaires List (2017). She attained the fortune when her father, industrialist Johan Andresen, transferred 42% of family-owned investment company Ferd to her. Her 21-year-old sister Katharina, who received the same amount, is the second youngest billionaire.