To support a consultation with transport providers in the aviation and rail sectors, the Office of Transport Regulation of the NMa, the Netherlands Competition Authority, commissioned a report from Oxera on the concept of buyer power in regulated transport sectors. The report describes the issues arising for regulation in the relative bargaining positions of infrastructure providers and their direct customers. It sets out, in an accessible way, what is meant by buyer power; the application of this to regulated sectors; factors that influence the degree of buyer power present; and the effects of buyer power on outcomes for end-consumers. A summary of the report was also commissioned and is available to download: Buyer power and its role in regulated transport sectors: summary report