Clemente Del Vecchio is the world's youngest billionaire at the age of 19 with $4 billion net worth, according to Forbes. He's the son of late Italian billionaire Leonardo Del Vecchio, who founded EssilorLuxottica, the world's largest eyewear company. Clemente became a billionaire after inheriting a 12.5% stake in his father's Luxembourg-based holding company Delfin following his death in 2022.