E.U. antitrust regulators are finalizing a charge sheet against Apple triggered by a complaint by Swedish music streaming service Spotify, two people familiar with the matter said, with one saying the document may be sent to the iPhone maker before the summer.

The case is one of four opened by the European Commission into Apple in June last year and could force the company to change its lucrative business model.

Spotify said Apple is unfairly restricting rivals to its own music steaming service Apple Music while another gripe is the 30% fee levied on app developers.

The E.U. competition enforcer usually sets out what it considers suspected violations of the bloc's antitrust rules in its statement of objections, whether a fine is merited and what companies have to do to stop anti-competitive practices.