Floyd Mayweather Jr.

Net worth: $450 million. "Money" Mayweather earned $1.1 billion from boxing — the highest career earnings in combat sports history. The Mayweather vs. Pacquiao fight (2015) generated $600 million in revenue; the McGregor fight (2017) generated $550 million. He keeps fighting exhibitions because each one generates $10-50 million for a few rounds of low-risk sparring. Mayweather owns a fleet of 100+ cars, a $26 million mansion in Las Vegas, and a stake in various nightclubs. He's 50-0 professionally and has never been shy about telling you exactly how rich he is.