MMA has taken off in recent years as one of the fastest growing sports around the world. The popularity is part of the reason why UFC owners are seeking to sell their share in the sport.

The winning bid, should the sell go through, would be upwards of $4 billion. There have been reportedly four bidders that have submitted their bid, including WME/IMG, China Media Capital, The Blackstone Group and Dalian Wanda Group. Zuffa LLC bought the UFC in 2001 for only $2 million and Dalian Wanda Group seem to be the favorite to purchase UFC. This is the same group that own 20 percent of Real Madrid and are partners with FIFA. They also own Hollywood films studios Legendary Entertainment.

"As a private company, we don't discuss speculation or rumors related to our business," said Dave Sholler, vice president of public relations and athlete marketing for the UFC.

UFC president Dana White has denied the rumors of the UFC being for sale.