The four publishers are Simon & Schuster, Harper Collins, Hachette Livre and Verlagsgruppe Georg von Holtzbrinck and their proposed commitments follow a settlement involving three of the four in the United States earlier on Wednesday.

Joaquin Almunia, the EU's competition chief, said he welcomed the proposals for an early resolution and was engaged in "fruitful discussions" with the companies.

Their suggestions would need to be assessed by "third-parties" before they could be accepted, he said.

The Commission launched an anti-trust case against the five publishers on December 6 2011 to determine whether the companies were colluding to raise the retail price of e-books.

Pearson Plc's Penguin group was not mentioned among those submitting proposals and the statement only said the investigation into the firm was ongoing.

If the Commission accepts the publishers' concessions, then the probe would be closed unless the companies fail to honor their agreements, in which case they can face a fine of up to 10 percent of annual turnover.

Three of these publishers - Simon & Schuster, Harper Collins and Hachette - have also reached a settlement with the U.S. Department of Justice.

The U.S. Justice Department and the European Commission have been trying to unravel agreements Apple secured with publishers about two years ago, when the Silicon Valley company was launching its iPad.

In some markets, e-books are showing dramatic growth rates. In Britain, the market share of e-book sales doubled in one year and is supposed to triple by 2015, according to figures from the Commission.

(Additional reporting by Barbara Lewis. Editing by Jane Merriman)

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