He has taken video of himself counting $1 million in hundred dollar bills, and posted photos where 50 Cent is balancing bricks of cash on his forearms.
His nickname is "Money," and his apparel business is called "The Money Team" - which also doubles as the name of his entourage.
So it should be no surprise that he keeps a significant portion of his assets in cash.
Mayweather has a single bank account with $123 million in it, according to an ESPN The Magazine feature by reporter Tim Keown.
Keown was with Mayweather in a Grand Rapids, Michigan Foot Locker when the boxer discreetly showed him his bank account receipt and said, "One account, baby."
Keown writes:
"I had heard that Floyd does his banking the old-fashioned way: going inside, talking to a real-life teller. He is also known to be a big proponent of maximum liquidity. Still, the amount of digits spread across the bottom-right corner doesn't seem possible."
Mayweather was the highest-earning athlete in the world from 2011 to 2012, making $85 million, according to Forbes.
It's unclear what his exact net worth is, but it's fair to assume that $123 million is a good chunk of it.
That net worth is set to grow even more in the coming weeks. Mayweather will have a $41.5 million payday when he fights Canelo Alvarez later this month, the largest guaranteed purse ever.
The call him "Money" for a reason.
His birthday cake:
With 50 Cent:
