In April 2012, the United States Department of Justice filed United States v. Apple Inc., naming Apple, Penguin, and four other major publishers as defendants. The suit alleged that they conspired to fix prices for e-books and weaken Amazon.com's position in the market in violation of antitrust law.[12] In December 2013, a federal judge approved a settlement of the antitrust claims, in which Penguin and the other publishers paid into a fund that provided credits to customers who had overpaid for books due to the price-fixing.[13]