A federal judge in the United States has denied a request by Orbitz Worldwide, Sabre Holdings and Travelport to have a lawsuit filed by American Airlines dismissed.

The suit alleges accuses the companies of antitrust violations.

The decision by United States district judge Terry Means in Fort Worth, Texas, had been under seal and was only made public following a request by the parties.

American Airlines accused the defendants of monopolizing how fares and flights are distributed to travel agents.

Orbitz is an online travel agency, Travelport provides transaction processing and Sabre runs a distribution system that delivers fare and flight information to travel agents.

“We continue to dispute these allegations and will defend ourselves vigorously, with the expectation that Orbitz will prevail,” Orbitz Worldwide spokesman Chris Chiames told Reuters.

Judge Means had previously dismissed some claims by American Airlines, but he allowed the company to submit a second amended complaint.

In his most recent decision, Means found that American had adequately alleged that the defendants engaged in a conspiracy to preserve their market power.