The attorney general of the state of Connecticut announced Monday that he is investigating whether Apple and Amazon digital book deals with publishers thwart market competition.
Amazon has deals with book publishers to sell digital versions of works for its popular Kindle electronic readers while Apple has struck similar business partnerships to provide titles for iPad tablet computers.
Prior to the iPad debut this year, Amazon was able to use its dominance of the e-reader market to offer best-selling works for 9.99 dollars each, a price that publishers complained was too low.
The makers of e-readers typically make deals with publishers to get permission to sell works and to convert works into digital formats compatible with devices.
Attorney General Richard Blumenthal said he grew concerned after finding no difference in price for digital versions of New York Times best-seller list books at Amazon, Apple, Borders, and Barnes & Noble.
"These agreements among publishers, Amazon and Apple appear to have already resulted in uniform prices for many of the most popular e-books - potentially depriving consumers of competitive prices," Blumenthal said.