The Wall Street Journal reports the U.S. Justice Department is investigating the pricing of ebooks to see whether there was "improper collusion" between publishers and Apple Inc. to prevent discounting.
Apple’s role in the investigation involves deals that pushed the so-called agency model, which allows publishers to set ebook prices instead of retailers.
There were also agreements blocking publishers from selling their titles at a cheaper price through other ebook stores.
A similar investigation is ongoing in Europe.
The EU's antitrust watchdog said Tuesday that it was investigating whether Apple helped five major publishing houses illegally raise prices for ebooks when Apple launched its iPad tablet and iBookstore in 2010, according to the Associated Press.