The U.S. Justice Department sued Apple Inc. (Nasdaq: AAPL) and five publishing giants Wednesday, accusing them of conspiring to fix prices for e-books.

The case was filed in U.S. District Court in New York by the department's antitrust division, which last year successfully opposed the takeover of T-Mobile USA by AT&T Inc. (NYSE: T). 

Shares of Apple, which soared at Wednesday's market opening to $636.87, fell $2.24 to $626.20 at the close.The company had no comment on the Justice Department lawsuit.

The book publishers named in the civil lawsuit are Hachette Book Group, part of French media conglomerate Lagardere SCA (EPA: MMB); HarperCollins, a unit of Rupert Murdoch's News Corp. (NYSE: NWS); CBS Corp.'s (NYSE: CBS) Simon & Schuster; Pearson PLC's (LON: PSON) Penguin Group (USA); and Macmillan, a unit of Germany's privately held Verlagsgruppe Georg von Holtzbrinck GmbH. 

The companies are accused of having overcharged consumers by as much as $100 million.

Negotiations over e-book pricing had been going on for much of this year but broke down, resulting in Wednesday's suit.

U.S. Attorney General Eric Holder said, Executives worked together to eliminate competition among stores selling ebooks, ultimately increasing prices for consumers at a press briefing.

Simon & Schuster, Hachette and HarperCollins announced an immediate settlement. Apple, Macmillan and Penguin have explicitly denied any collusion on the pricing of e-books. They will remain in the case.

'Undo the harm'

Assistant Attorney General for Antitrust Sharis Pozen, who led the case against AT&T before the e-books probe, hailed the partial settlement. It will begin to undo the harm caused by the companies' anticompetitive conduct, she said.

New York-based Macmillan confirmed it wouldn't settle with the government. While the publisher had engaged in settlement discussions, the terms the DOJ demanded were too onerous, CEO John Sargent said in a statement cited by the New York Times.

Defendants' ongoing conspiracy and agreement have caused e-book consumers to pay tens of millions of dollars more for e-books than they otherwise would have paid, the lawsuit said.

In a separate suit brought by states against the publishers was also partially resolved. Hachette and HarperCollins settled with an agreement to pay a combined $52 million. The other publishers didn't settle.

This scheme would have cost consumers millions in excessive prices and stifled the development of an important form of e-commerce, said David Balto, a lawyer who was head of policy for the U.S. Federal Trade Commission in the administration of President Bill Clinton.

Amazon hails lawsuits

As Apple's dominance of the media market has grown with thousands of titles available for download over its iPad platform, its pricing power has attracted attention as well as notice from rivals such as Amazon.com Inc. (Nasdaq: AMZN), which sells the Kindle and Kindle Fire tablets, as well as from Barnes & Noble Inc. (NYSE: BKS), seller of the Nook.

The Justice Department complained that Apple, prior to introducing the iPad tablet in 2010, colluded with the publishers to get their titles as low ads $9.99 for newly released and best-selling e-books, cheaper than through Amazon.com or Barnes & Noble. Apple, of Cupertino, Calif., and the publishers countered that their practices have constrained Amazon.

This is a big win for Kindle owners, an Amazon spokesman said. We look forward to being able to lower prices on more Kindle books. Barnes & Noble didn't have a statement.

Shares of Amazon rose 99 cents to $187.97 in  Wednesday trading while Barnes & Noble fell 19 cents to $11.73.  Both had risen sharply when the lawsuits were announced earlier.