You would think that a lawsuit like this might come from a direct competitor, but that’s not the case. Instead, the antitrust lawsuit is being filed by the United States government, naming Apple and several book publishers as the defendants.
The allegation is that Apple colluded with several book publishers to keep the prices of e-books higher in an effort to limit competition. More specifically, it says that this collusion was in direct response to the lower prices being offered by Amazon, which is known to sell best-seller e-books at $9.99. The publishers still wanted their books sold, but at $9.99, they weren’t making enough money.
And thus, the publishers had the same goal as Apple: keep the prices higher. It is “hard to settle a lawsuit when you know you have done no wrong,” said Macmillan (Holtzbrinck Publishers) CEO John Sargent. “Macmillan did not collude.”
The iBookstore from Apple is estimated to have about a 10-15% market share among e-books, compared to the around 60% that the Amazon enjoys, though that figure is down from the 90% it had some time back.[Source]