The Ultimate Fighting Championship (UFC), featuring such stars as Michael Bisping and Conor McGregor, has been sold for about $4bn (£3.1bn), according to reports in the United States.
An official announcement is expected on Monday.
Reports claim a group led by Hollywood talent agency WME-IMG has purchased the mixed martial arts promotional company.
Founded in 1993, the UFC was bought for $2m (£1.55m) in 2001 by brothers Lorenzo and Frank Fertitta.
It describes itself as the fastest-growing sports organisation in the world, producing more than 30 live events worldwide each year.