The European Commission's competition watchdog has opened a probe into Amazon's ebook business.
The EC announced the antitrust investigation on Thursday, which will look into "certain business practices" around Amazon's ebook distribution business.
The Commission will be looking into the contracts Amazon signed with publishers, which compel them to let the company know when it offers rivals better or different terms, match any better terms offered to competitors, or otherwise make sure Amazon is getting as good a deal as any other distributor.
The EC is concerned that such practices could constitute a breach of European antitrust law, harming competition and giving consumers a worse deal. "The Commission has concerns that such clauses may make it more difficult for other e-book distributors to compete with Amazon by developing new and innovative products and services," the EC said.
The EC's competition commission will start by studying Amazon's behaviour in the largest ebook markets in Europe, the UK, and Germany.
Amazon is the largest ebook seller on the continent, where the market for digital books is estimated to be worth between $11bn and $15bn annually. In 2013, Forrester predicted that Europe would be the largest ebook market in the world, and worth $19bn.
Margrethe Vestager, the EU's commissioner for competition policy, said: "Amazon has developed a successful business that offers consumers a comprehensive service, including for e-books. Our investigation does not call that into question. However, 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."
Amazon said in a 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."
The probe follows an earlier investigation into the ebook market, which began in 2011 and saw Apple and five publishers investigated by the EC's competition authority. All of the companies, which had been thought to be limiting competition on pricing, eventually made settlements that addressed the Commission's concerns.