Kylie Jenner — "Billionaire" at 21 (Debated)

Forbes declared Kylie Jenner the youngest 'self-made' billionaire at 21 in 2019, then revoked the title in 2020 over inflated revenue claims. She sold 51% of Kylie Cosmetics to Coty for $600 million, valuing the company at $1.2 billion. Whether she was ever technically a billionaire remains debated, but the $600 million exit before age 23 with just seven employees is indisputable. Her Instagram lip kits sold out in 30 seconds, and compared to Alexandr Wang's #3 purely tech trajectory, Jenner's beauty empire relied on social media virality—a strategy that is 50% more profitable than the average celebrity brand.