[mlader]

Apple and a number of publishers have already settled with the EU Commission [1], which began an investigation before even the DOJ. From a legal standpoint this is not an admission of guilt. Apple believed that either a) the legal costs of mounting a defense were about the same as the potential damages, b) they could not win in the European Courts (this could be because of the interpretation of their anti-trust laws), or c) the PR debacle would harm their brand and reputation too much. I would pick a combination of B and C in this case, though mostly B.

As far as the DOJ anti-trust division is concerned, their job is to investigate and prosecute companies that allegedly partake in anti-competitive behavior that adversely affect consumer prices. They saw a rise in prices as competition increased, which is contrary to how price dynamics are supposed to work in an increasingly competitive market. Given that the source of this rise in prices was due to simultaneous pressure from publishers on Amazon to switch to an agency pricing model from a wholesale pricing model, it makes sense that the DOJ would investigate. This suit will likely take a few years to come to a conclusion.

[1] http://www.macworld.co.uk/ipad-iphone/news/?newsid=3353332&#...