The European Union’s founding treaties recognize the need for a balancing exercise between protective interests and the principles of openness, transparency, and the right of access to documents. Nowhere is that balancing exercise as evident as in the field of trade defence investigations. There, primary EU law principles meet the restrictions arising from the Union’s international law obligations under the WTO Agreements as well the sectoral EU law system of protection of confidential information. What is more, to-date, the Court of Justice of the European Union is yet to provide guidance on how that system should be untangled. This article assesses the interplay between those (at first sight competing) frameworks. In so doing, it will look at the intricacies of the law surrounding EU trade defence investigations and the public right of access to information under Regulation (EC) 1049/2001. Guided by the case-law in those areas and other fields of EU law, the article will discuss how that interplay of rights and restrictions should be resolved if and when the issue is put before the General Court or the European Court of Justice.