The European Commission has opened an investigation into Amazon’s e-book business, over fears that it could be stifling competition.

The EC will be particularly looking into clauses in Amazon's contracts that require publishers to inform the US firm about deals they have with its rivals.

The move is the latest in a series of investigations instigated by the new EC competition commissioner Margrethe Vestager who has already started looking into several US giants including Apple, Starbucks and Google.

Ms Vestager said in a statement: "It is my duty to make sure that Amazon's arrangements with publishers are not harmful to consumers, by preventing other e-book distributors from innovating and competing effectively with Amazon. Our investigation will show if such concerns are justified."