Apple has lost its appeal of a federal court decision that found it broke antitrust law by colluding with publishers to fix the prices of ebooks.
The US Second Circuit Court of Appeals upheld a 2013 ruling by the US District Court of the Southern District of New York that found Apple had sought to artificially inflate ebook prices.
"The decision confirms that it is unlawful for a company to knowingly participate in a price-fixing conspiracy, whatever its specific role in the conspiracy or reason for joining it," said US Assistant Attorney General Bill Baer.
"Because Apple and the defendant publishers sought to eliminate price competition in the sale of ebooks, consumers were forced to pay higher prices for many ebook titles."
The ruling upholds an earlier decision against Apple over the way it handled pricing on its iBooks service. The court found that Apple conspired with US book publishers Hachette, Harper-Collins, Macmillian, Penguin, and Simon & Schuster to fix ebook prices.
While the book publishers involved in the case all eventually settled with the government, Apple decided to fight the case on its own and to appeal the district court's verdict.
Having lost that effort, the Cupertino giant will now need to pay the $450m judgment against it, which includes $400m to be returned to consumers.
Apple remained defiant following the ruling, however, and denied any wrongdoing.
"Apple did not conspire to fix ebook pricing and this ruling does nothing to change the facts," Apple told The Reg in an emailed statement. "We are disappointed the Court does not recognize the innovation and choice the iBooks Store brought for consumers. While we want to put this behind us, the case is about principles and values. We know we did nothing wrong back in 2010 and are assessing next steps." ®