The United States Justice Department has warned Apple and five of the largest U.S. publishers that it plans to file an anti-trust suit against them. Citing people familiar with the matter, the Wall Street Journal reports that the suit will accuse Apple, Simon & Schuster, Hachette Book Group, Penguin Group, Macmillan, and HarperCollins of colluding to raise the price of electronic books. Several of the parties have held talks to settle the case and prevent a court battle, according to the report, and such a settlement could lead to cheaper e-book pricing. Not every publisher is in settlement discussions, however. The companies are also being investigated by the European Union over the same alleged offense.