HAUPPAUGE, N.Y. — The period to add plaintiffs to a $350 million antitrust case against Carfax is drawing to a close, according to the law firm handling the lawsuit. The suit, which alleges that Carfax has illegal alliances with key players in the auto industry, has reached nearly 900 dealer plaintiffs since it was first filed in April 2013.

“I have listened to dealers across the nation complain that Carfax has abused its monopoly power, which they claim has resulted in inferior vehicle history reports, exorbitant pricing, and a marketing campaign designed to disparage and denigrate auto dealers,” wrote Bellavia Blatt Andron & Crossett, P.C. Senior Partner Leonard Bellavia in a letter to prospective plaintiffs. “We investigated Carfax's business model and determined that, in our opinion, Carfax has violated various anti-trust statutes.”

In the next two months, the firm is hoping to add 300 dealers to the case. The mass action suit is seeking recovery of alleged substantial overcharges over a six-year period, multiplied by three, in accordance with the anti-trust laws.

If the expected number of dealer plaintiffs is reached, it will be the first time over 1,000 dealers have joined forces to sue a key player in the industry, according to the firm.