1. Introduction – 2. Public undertakings as economic operators in procurement markets – 3. The issue at stake: cross-subsidisation of reserved activities – 4. How to prevent cross-subsidisation: separation of accounts, cost allocation and benchmarking 5. How to detect cross-subsidisation in procurement context:  Article 69(4) of Directive 2014/24/EU – 6. Critical assessment of the provision – 6.1. The monopoly of the Commission on the substantive assessment of compatibility of the aid – 6.2. Misused aids cannot be excluded – 6.3. The ratio of the norm fails in case of public undertakings – 7. The enforcement of the mechanism at national level: Italy as a case study.  

This paper discusses the law of the European Union (EU) on public procurement by providing an overview of both the primary law principles and  foundations emanating from the Treaty on the Functioning of the European Union (TFEU) and the detailed rules of a set of secondary procurement Directives. The latter have to be transposed into the national laws of the 28 Member States and are then applied by their contracting authorities and entities. The analysis also includes the relevant case law of the Court of Justice of the European Union (CJEU) and a short evaluation of the principles applying to contracts falling outside the field of application of the procurement Directives.