Yesterday, US District Court Judge Denise Cote granted class certification to plaintiffs in a lawsuit over Apple's alleged e-book price-fixing.

Cote last year ruled that Apple led a conspiracy with publishers to raise e-book prices above those charged by Amazon. That lawsuit was filed by the Department of Justice, but there was also a class action suit filed on behalf of book buyers by the Hagens Berman law firm.

"After a bench trial in two closely related cases, defendant Apple Inc. was found to have colluded with five major publishers to fix e-book prices, violating Section 1 of the Sherman Antitrust Act," said Cote, a federal judge in the southern district of New York, in her decision.

Plaintiffs sought class certification "in their action against Apple based on the same conduct" and "have more than met their burden" to establish that the certification should be granted, according to the ruling (PDF).

"Virtually all class members paid inflated prices for e-books as a result of a centralized price-fixing conspiracy, and they have proffered a sophisticated damages model to reliably determine damages," she also wrote.

Cote's ruling last year came with a range of punishments intended to prevent future price-fixing, but the ruling did not include financial damages. Plaintiffs in the class action suit are seeking more than $800 million, according to Reuters. A trial will likely take place in either July or September, Reuters wrote.

Apple appealed Cote's ruling in the case filed by Justice officials, arguing last month that higher new release prices boosted competition and that antitrust laws aren't designed to "keep prices down at any cost."

Although Apple fights on, Hachette, HarperCollins, Simon & Schuster, Macmillan, and Penguin all settled their cases and agreed to pay damages of more than $160 million. Amazon just started issuing refunds made possible by those settlements.