State-owned and other state-invested enterprises (SIEs) have become more prominent in the global economy over the last decade. A growing role for state-invested enterprises in the marketplace is not in itself onerous. According to an OECD consensus, as expressed through the Organisation’s legal instruments, SOEs can be operated according to similarly high standards of governance, transparency and efficiency as private companies, in which case the ownership issue is moot. However, only some of the world’s most advanced economies, following decades of reform of their SOE sectors, have approached this point. Moreover, when SOEs operate across borders the challenges may multiply. With this background, this paper compares the difference between SIEs and non- SIEs in five sectors: air transportation, electricity, mining, oil & gas and telecommunication. The empirical analysis indicates that, in addition to any financing advantages, large state-invested enterprises also seem to benefit from an unusually favourable position in their home markets. A comparative analysis further shows that, in the course of the last ten years, SIEs have generally enjoyed higher rates of return than comparable private companies. The paper concludes that the growing role of state-invested enterprises in the international marketplace does not yet present a serious macroeconomic challenge. However, since it is likely to keep growing for some time, challenges need to be addressed relatively soon. This makes for a strong case for enhanced policy coordination and information sharing. If legally binding instruments cannot be developed in the near to medium-term to ensure competitive neutrality, consultation mechanisms could be established through which the main players in international trade and investment can exchange views on matters of common concern related to the state in the marketplace. The ultimate purpose would be ensuring that the international trade and investment environment remains open, non-discriminatory and offering a level playing field.