The European Commission (EC) has reportedly begun a formal anti-trust probe into Amazon's book business.
The commission will examine clauses in Amazon's contracts that require publishers to inform the US firm about deals they have with its rivals, reported the BBC.
A statement released by the new EC Competition Commissioner Margrethe Vestager said that the move was aimed at ensuring that Amazon's arrangements with publishers were not harming consumer interests by holding other e-book distributors from innovating and competing effectively with Amazon.
The firm, which owns the Kindle e-reader, is already under pressure for paying lower tax rates in Luxembourg.
