The European Commission (EC) has launched an anti-trust investigation into online retail giant Amazon’s ebook business.

The commission will look into clauses in Amazon’s contracts that require publishers to inform the US retailer about any deals they have signed with rival firms.

According to the EC, the clauses could make it more difficult for other ebook distributors to compete.

New EC competition commissioner Margrethe Vestager is already probing the tax affairs of Apple and Starbucks and launched an investigation into Google’s online business practices in April.

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 ebook distributors from innovating and competing effectively with Amazon.

“Our investigation will show if such concerns are justified.”