Jeff Bezos' siblings, Mark and Christina, took a leap of faith by investing $10,000 each in a fledgling online book store.
Susquehanna's Jeff Yass now ranks 23rd on the Bloomberg rich list with a $63 billion fortune, reflecting his early bet on TikTok-owner ByteDance.
The South Africa-born billionaire once suffered the largest loss of a personal fortune in history, according to Guinness World Records. He has since recouped that money and more.