The four publishers are Simon & Schuster, News Corp unit HarperCollins, French group Lagardere SCA's Hachette Livre and Verlagsgruppe Georg von Holtzbrinck, which owns Macmillan in Germany.
The publishers have agreed deals with Apple under which online versions of their books sell for set prices on Apple's iTunes, with Apple taking 30 percent of the proceeds. The deals specified that other retailers, such as Amazon, could not sell the e-books at a lower price.
The Commission said in April that the five companies had offered concessions in a bid to end the investigation and avert penalties which could reach 10 percent of their global turnover, but it did not give details.
Pearson Plc's Penguin group, which is also being investigated, was not mentioned among those submitting proposals.
Full story at Reuters