It was a surprise two weeks ago when one entry popped up on the Nevada Athletic Commission’s (NAC) meeting agenda: The UFC was requesting to be a co-promoter for the Floyd Mayweather vs. Conor McGregor boxing event.

UFC president Dana White had long said Mayweather vs. McGregor would not be a UFC production and that his organization would not be an official promoter — just helping Mayweather Promotions and Showtime push the mega fight.

There’s a good reason why the UFC requested, and was then granted last week, co-promoter status for MayMac, which takes place Saturday at T-Mobile Arena in Las Vegas.

It had to be, NAC executive director Bob Bennett told Ariel Helwani on Monday’s episode of The MMA Hour.

The UFC needed to be a promoter, Bennett said, in order to pay McGregor his share of what is likely to be a windfall of revenue. If Mayweather Promotions remained the sole promoter of the event, the main event would have broken NAC rules. If a promoter is also a fighter, in this case Mayweather, he or she cannot pay his or her opponent for the bout.

“Floyd can’t pay his opponent,” Bennett said. “The UFC is a co-promoter, because they’ll be paying Conor. … Otherwise it would have been a conflict of interest — an opponent paying the other opponent.”

The rule comes from NAC 467.112 of its official regulations, which stipulates “a bout agreement which provides that an unarmed combatant is to pay for the services of his or her opponent is prohibited.”

TGB Promotions, the lead promoter for Al Haymon’s Premier Boxing Champions, also applied for and was granted co-promoter status for Mayweather vs. McGregor at the NAC meeting last week.

White was seen wearing a “Zuffa Boxing” t-shirt multiple times during the MayMac World Tour last month. But Mayweather vs. McGregor is being promoted by the plain old UFC. McGregor remains under UFC contract, even if this is a boxing match. Bennett said in Nevada licenses for promoters do no differentiate between MMA and boxing.

“They’re a promoter on record,” Bennett said of the UFC. “Our promoters license doesn’t state whether you have to be a boxing promoter or an MMA promoter.”