A class-action lawsuit was filed against UFC in 2015 accusing the mixed martial arts giant of abusing its power to cripple the market and create a monopoly on the MMA world.

While the antitrust suit claims UFC demands exclusivity for its fighters, UFC had asked for the antitrust case to be dismissed. The case still lingers, and UFC filed subpoenas that would allow its lawyers to see key financial and contract information on fighters who may be competing on other professional circuits.

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UFC's main competitor, Bellator, then filed a lawsuit Wednesday seeking to quash those subpoenas. The suit was filed in the U.S. District Court for the Central District of California.

Bellator said in an affidavit that it has already "produced in excess of two thousand pages of responsive documents" pertaining to the antitrust case.

UFC wants more information, including copies of Bellator's contracts with MMA fighters and detailed financial records to help defend itself in the antitrust suit.

Bellator contends that information is confidential and "the subpoenas improperly seek trade secret and other sensitive information protected from disclosure; they are overbroad and unduly burdensome; and this information cannot be adequately protected by the litigants’ stipulated protective order."

According to the 2015 antitrust suit, UFC stands accused of running "an illegal scheme to eliminate competition from would-be rival MMA Promoters by systematically preventing them from gaining access to resources critical to successful MMA Promotions, including by imposing extreme restrictions on UFC Fighters' ability to fight for would-be rivals during and after their tenure with the UFC."

Bellator president Scott Coker, who founded Strikeforce before selling it to UFC in 2011, said in a court document that Bellator "is not a party" in the antitrust case. He stated Bellator should not have to "produce some of the confidential documents that the Parties have demanded, as doing so would lead to grave harm to Bellator."

"Accordingly, disclosure of Bellator's confidential information pursuant to the Nevada subpoena would give Bellator's largest and most powerful competitor a significant and unilateral advantage that would negatively harm Bellator and, in my opinion stifle competition in the MMA industry," Coker said to conclude an eight-page statement.