The Fertitta brothers recently agreed to sell UFC to a combination of investor groups for $4 billion, a huge return on their original $2 million investment. The sport has grown wildly from its original no-holds-barred beginnings, and rivals other sports franchises in popularity. In this clip from the Motley Fool Money radio show, Chris Hill and Ron Gross talk about how huge the UFC has grown since the Fertittas bought it 15 years ago and where it has to grow from here. A full transcript follows the video. A secret billion-dollar stock opportunity The world's biggest tech company forgot to show you something, but a few Wall Street analysts and the Fool didn't miss a beat: There's a small company that's powering their brand-new gadgets and the coming revolution in technology. And we think its stock price has nearly unlimited room to run for early-in-the-know investors! To be one of them, just click here.{%video%} This podcast was recorded on July 15, 2016. Chris Hill: Fifteen years ago, Lorenzo and Frank Fertitta bought UFC, the mixed martial arts franchise for $2 million. This week, they sold it to a combination of investor groups for $4 billion. It is the single largest franchise sale in sports history. That is a nice return on investment, Ron. Ron Gross: Boy, boy oh boy, this is hot. It's an incredible deal. William Morris, probably a lot of people know, is the agency... Hill: IMG, the big global sports conglomerate. Gross: So, it was a combination of William Morris and IMG. They have partners in this. Michael Dell is a partner, Kohlberg Kravis, Silver Lake, all partners. The owners, the brothers had an 80% stake. They'll maintain a minority stake. Dana White was another 10% owner of this; he's going to stay at the president going forward. But obviously, UFC, very popular. 40 live events a year, 156 countries, they have 46 million social media followers, which is an important avenue for them to get out their content. For $4 billion, they're expecting big things here. Fox (NASDAQ: FOX) (NASDAQ: FOXA) has the TV rights, but that will come up for renewal in 2018. Look forward to that. Hill: Yeah, they're getting $100 million a year from Fox. As you said, in two years, that comes up. I'm guessing the bidding will start at $200 million. Gross: It's going to be big, absolutely. Don't be surprised if we see William Morris, WME, come out with an IPO in the next year or two, because it looks like they're raring to go with that. Chris Hill has no position in any stocks mentioned. Ron Gross has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.