As a federal appeals court continues to review a lower court’s ruling against Disney, Fox and Warner Bros. Discovery, pay-tv operator Fubo has reasserted its main argument against the media giants.

Venu Sports, the joint venture backed by the companies, would “substantially” lessen competition, Fubo argued in a brief filed Monday. (Read the full brief Here.)

The companies have given Venu “a built-in advantage: the exclusive right to distribute their combined, commercially critical sports content without also having to pay for – and force viewers to pay for – unwanted non-sports channels.” Furthermore, Disney, Fox and Wbd “have structured the Jv to avoid anything like competition on the merits. Its artificial advantage will capture hundreds of thousands of subscribers and tens of millions of dollars from Fubo alone, driving Fubo into insolvency, and destroying or damaging other distributors.”

After the three media companies formed the streaming venture last February, Venu Sports,...