Floyd Mayweather was willing to put his money where his mouth was against Conor McGregor. (John Gurzinski / AFP / Getty Images)

How much is too much money?

Silly question, especially if your name is Floyd Mayweather. The boxer who makes Las Vegas his home has often shared images of how big his bets pay off on social media and, just before a fight against Conor McGregor that he said would bring him around $300 million, he was so confident of his impending victory that he tried to get a little more action.

There’s no law preventing fighters from betting on themselves and, even at 40 and almost two years removed from his last fight, Mayweather was 49-0 going into Saturday night’s fight against a UFC star who had never before fought under the constraints that govern boxing. Seems like a pretty safe bet.

So, at around 3:30 p.m., Mayweather strode into the sportsbook at the M Resort with $400,000 in cash and the itch to wager, according to ESPN. With an over/under for the fight of 9.5 rounds, betting the under would have brought a payout in a fight that Mayweather won with a TKO barely into the 10th round. Sounds like a man with a plan, right? Unfortunately, he couldn’t get the bet at -200 odds.

Unfortunately, a source told the network that there was a delay over concerns about the legality of a fighter betting on anything other than a straight win. And there was also a delay when Mayweather tried to place a bet on himself to win by knockout. An impatient Mayweather — described to ESPN by an unnamed source with an expletive for “angry” — left without wagering.

As fate — or perhaps his game plan — would have it, Mayweather, who reportedly is facing a 2015 tax bill, would have won his either of his attempted bets because the fight was stopped 1 minute and 5 seconds into the 10th round. Luckily, the fighter known as “Money” has friends and one of them was allowed to put down $87,000.

Read more on the fight:

Mayweather says he’s going back to retirement, so what’s next for McGregor?

A round-by-round recap of Mayweather-McGregor

Demi Lovato’s national anthem was the night’s biggest winner

There were some pretty big stars outside the ring, too

‘I owe them for the Pacquiao fight’: Mayweather has a message for fans