There’s no denying it. Floyd “Money” Mayweather Jr. is undoubtedly one of the greatest boxers of all time, but casual observers might know him more for his spending habits than his spotless record. That wasn’t always the case, though. Early on in his career, he was an excellent boxer with sharp technical skills (and still is), but he was far from a pay-per-view draw.

What’s particularly impressive about Mayweather’s huge paydays is that his hallmark has been his spectacular defense. With a style that wasn’t always fan-friendly, he still managed to make more than the sport’s most ferocious knockout artists. How did he do it? With decades of hard work and several savvy business moves.

Mayweather’s career earnings have surpassed $700 million. After his bout with Conor McGregor, he may reach a billion dollars in career earnings. According to Forbes, the only other athletes to cross that 10-figure line are: Michael Jordan ($1.5 billion), Tiger Woods ($1.4 billion), Arnold Palmer ($1.35 billion), Jack Nicklaus ($1.15 billion) and seven-time F1 racing champion Michael Schumacher ($1 billion).