Floyd Mayweather Junior said even the "crazy numbers" he has been offered to resume his boxing career will not tempt him to return to the ring.
The 38-year-old feels he has nothing left to prove after beating Andre Berto in Las Vegas last September to match legendary heavyweight Rocky Marciano's 49-0 unbeaten record.
In an interview with BBC World Service Sport, Mayweather revealed he could pick up a "nine-figure sum" by boxing again, but the American former pound-for-pound king has ruled out a comeback - for the time being at least.
He said: "As of right now, I am out completely.
"If I do get the itch to come back, it really won't be for the money but I have to get paid. That's why the nickname is Floyd 'Money' Mayweather."
Mayweather also dismissed claims that talks had been held over a potential rematch with Manny Pacquiao.
The pair fought in the most lucrative bout in history last May, with Mayweather outboxing his opponent to claim a unanimous decision.
"Everything that you guys are hearing that Michael Koncz [Pacquiao's business advisor] has said and what [promoter] Bob Arum has said is totally false. Totally false. I haven't spoken to Bob Arum, I haven't spoken to Michael Koncz," he added.
"And as far as people keep talking about Mayweather Promotions, I dictate and control what goes on with it. Leonard Ellerbe is the CEO but everything has to go through me and I have to put the green light on any and everything."
Mayweather believes he should go down as the best fighter of all time given his achievements in the sport.
"I really wouldn't want to say the best pound-for-pound fighter in the world - you know, I am no longer active. I would like to say the best ever," he added.
"It's not being cocky or arrogant, it's just the proof is in the pudding. I think I have earned the right to call myself TBE [the best ever]. And I have lived up to the name TBE by going out there, day in, day out, when I was active and winning.
"Have I have ever took a loss before? Yes. In life, you lose a loved one, that's taking a loss. When your children hurt, that's a loss. When you are sick, that's a loss.
"But I got to where I got to from a lot of hard work, a very strong team, a smart team that stood behind me."