The EU launched its investigation in December, several months after the US Department of Justice began its inquiry.
According to the lawsuit filed yesterday, executives at the publishing houses spoke regularly and met at "upscale Manhattan restaurants" to discuss Jobs' offer.
They took pains to cover their tracks, ordering certain emails be "double deleted".
The cost of the scheme to shoppers could be as much as US$100 million ($122 million), according to Connecticut Attorney General George Jepsen.
Eric Holder, the Obama Administration's Attorney-General, said US$2 or US$3 was added to the average price of an e-book. "We believe that consumers paid millions of dollars more for some of the most popular titles," he said.
Apple's entry into the e-book market, with the launch of the iPad and the related iBookstore in 2010, revolutionised the market.
Until then, Amazon's e-book store operated like a high street bookshop chain, paying a wholesale price and then selling e-books at a price of Amazon's choosing. To boost sales of the Kindle in the US, they were being sold at a knock-down price of US$9.99.
That was a figure the publishers thought was too low. Apple's "agency" model would allow publishers to set the customer price directly, at whatever level they wanted.
The business agreement, which all the publishers signed within days of each other, stipulated that they would not let anyone else sell e-books for less than Apple.
The UK's Pearson Group, owner of Penguin books, is among the five publishers sued in the US. The others are Macmillan, Hachette, Simon & Schuster and Rupert Murdoch's HarperCollins. The last three immediately agreed settlements with the US Government.
- Independent