While that figure was slightly exaggerated -- UFC had been sold for $4 billion a few months earlier -- there's no doubting McGregor is very much the face of the franchise.
But there's one fight club where McGregor's larger than life personality wouldn't be altogether welcome -- ONE Championship, UFC's mixed martial art equivalent in Asia -- according to the franchise's founder Chatri Sityodtong.
"If Conor McGregor was a free agent, ONE Championship would not try to sign him," Sityodtong told CNN.
"We don't want somebody to swear at people, throw water bottles, disrespect people, call out people's wives and children, and -- in my opinion -- other distasteful stuff that is not representative of true martial arts.
"We have heroes like Angela Lee, who is pound-for-pound one of the best female world champions on the planet. But yet she is humble, she is kind, she's sweet.
"You have Eduard Folayang, who came from extreme poverty, conquered so many impossible odds. He's so humble, gentle and kind. These are the heroes I want to support in ONE Championship."
McGregor's representatives are yet to respond to CNN's request for comment.
Sityodtong himself is no stranger to poverty, perhaps explaining why he identifies so closely with the humility his fighters exude.
Born in Thailand, he was raised in a wealthy family thanks to his dad's lucrative property company.
However, just before leaving to study at Harvard University in the late 1990s, the Asian financial crisis struck and his family lost everything: their business, their money, even their home.
Sityodtong says his mother, "through her love," convinced him to go anyway, before finding enough money to fly over and live with him in his dorm.
At his lowest ebb, he says, he had to survive on $4 a day.
"I was very lucky that there was a Korean buffet place nearby school," Sityodtong says. "For a little over three dollars, I could have all I could eat, and so I would relish that moment.
"Whenever I thought that things were at a low-point, there were tougher days and tougher days."
Using the martial arts skills he learned growing up, Sityodtong began teaching Muay Thai on the side to earn more money for him and his mother.
He and a fellow university pupil then created a software start-up while at Harvard, eventually selling it for an undisclosed fee after graduation.
Though not enough to consider retiring completely, the figure he received provided his escape from poverty.
A successful stint on Wall Street followed, culminating in the opening of his own hedge fund business Izara Capital Management.
Even so, despite being a multi-millionaire in his late 30s, something was still missing.
"When I was dirt, dirt poor, I thought that if I made millions and millions -- that if I had money -- there'd be no problems and I'd be happy," says Sityodtong. "And the reality is that I was empty inside."
So he decided to quit his job and pursue his first passion: martial arts.
He noticed that in almost every region of the world there were several multi-billion dollar sporting organizations.
North America has the NFL, NBA, NASCAR, UFC and Major League Baseball, he says, which are all worth in the region of $4 billion to $30 billion.
Likewise in Europe, the continent's biggest football leagues and Formula One are worth between $2 billion to $30 billion each.
Sityodtong believed he had spotted a gap in the market on the Asian continent, noting there was "nothing, literally nothing on a Pan-Asian basis" that could compare to sport industries in other parts of the world.
The India Premier League, a billion-dollar cricket franchise, was the only organization of real note, while there were also a few smaller football leagues.
"But nothing of significance," Sityodtong explains. "So I thought to myself: what is more Asian than martial arts? And no one had ever tried to unite four billion people -- the world's largest population base -- around one sports property.
"And I said 'man, there's got to be a way.'"
'The DNA of the Asian audience'
And so ONE Championship -- originally launched as ONE FC in 2011 -- was born.
In an interview with CNN Philippines in June, Sityodtong predicted that ONE Championship would pass the $1 billion valuation mark "in about 18-months."
Now in its seventh year, ONE Championship is sponsored by the likes of Disney, Under Armour, Sony and Facebook, among many others, and in 2012 signed a lucrative 10-year television deal with ESPN Star Sports, since rebranded as Fox Sports Asia.
Its immediate success even convinced Manny Pacquiao to purchase shares in the company in 2014.
Fighters in ONE Championship can use any form of martial arts, meaning a black belt in karate could go up against a brown belt in taekwondo.
"We understand the DNA of the Asian audience," explains Sityodtong.
"We connect deeply; we connect deeply culturally, historically, traditionally by showcasing the beauty of true martial arts, as opposed to glorifying the fight.
"So I think UFC is a fight, UFC is a sport. ONE Championship is martial arts."