Amazon's e-book business is facing an antitrust investigation in Europe, where the European Commission says the company's contracts with publishers contain "clauses which seem to shield Amazon from competition from other e-book distributors."

These clauses give Amazon "the right to be informed of more favorable or alternative terms offered to its competitors; and/or the right to terms and conditions at least as good as those offered to its competitors," the EC said in its announcement today

"The Commission will now investigate further whether such clauses may hinder the level playing field and potentially decrease competition between different e-book distributors to the detriment of consumers," it said. The clauses "may make it more difficult for other e-book distributors to compete with Amazon by developing new and innovative products and services," the commission said.

The EC stopped short of declaring Amazon guilty. "Our investigation will show if such concerns are justified," EU Commissioner in charge of competition policy, Margrethe Vestager, said.

There is no deadline for finishing the investigation.

When contacted by Ars, Amazon offered this statement: "Amazon is confident that our agreements with publishers are legal and in the best interests of readers. We look forward to demonstrating this to the Commission as we cooperate fully during this process.”

Apple faced similar allegations in the US, ultimately agreeing to a $450 million settlement. Apple's contracts with publishers prevented the company from having to compete on price and compelled the publishers to raise prices on Amazon's Kindle store to match those being charged on Apple's, a federal judge in that case ruled.