The EU Court of Justice states that the Commission can reject a complaint on the ground that the complainant can bring an action to assert its rights before national courts (Tremblay)

Case T-5/93 Roger Tremblay and Others v Commission of the European Communities* 1. The statement of reasons on which a decision adversely affecting a person is based must, first, be such as to enable the person concerned to ascertain the matters justifying the measure adopted so that, if necessary, he can defend his rights and verify whether the decision is well founded and, secondly, enable the Community judicature to exercise its power of review as to the legality of the decision. However, the Commission is not obliged, in stating the reasons for the decisions which it takes to ensure the application of the competition rules, to adopt a position on all the arguments