Portrait of Guillaume Castroviejo

Guillaume Castroviejo : Consultant

Guillaume is a member of Oxera’s Regulation and Market Design team. He specialises in the economic regulation of infrastructure and utilities.

He joined Oxera in 2021, after completing a Master’s degree in Economics of Markets & Organizations at Toulouse School of Economics, and a double Bachelor’s degree in Economics and Mathematics and Computer Science. During his studies, he specialised in microeconomics, game theory, regulation and competition economics, and spent a year at the University of Reading attending competition and regulation courses. He also spent a year teaching microeconomics to undergraduate students in Economics and Law at the University of Toulouse Capitole.

Guillaume provides advice to water and energy companies in the context of cost assessment modelling, and has undertaken several regulatory due diligence assessments. He writes regularly for Oxera’s Agenda publication.

Guillaume speaks English, and French.

Tel: +33 (0) 1 80 20 91 84

Guillaume's specialisms include:

professional experience

  • Advice on the acquisition of a stake in Northumbrian Water (2022)

  • Advice to SSE on the divestment of a stake in its electricity transmission business (2022)

  • Market power assessment and advice on regulatory issues to a French airport (2022)

  • Provided support to a sports betting company in its state aid procedure with the European Commission (2021–22)

  • Economic analysis of alleged coordinated behaviour between European beverage producers (2021–22)

  • Ongoing work advising several UK water companies in the context of cost-assessment modelling in preparation for Ofwat’s PR24 price review (2021–)


  • MSc Economics of Markets & Organizations, Toulouse School of Economics, France

  • BSc Economics, Toulouse School of Economics, France

  • BSc Mathematics and Computer Science, University Toulouse 1 Capitole, France

Latest Insights:  Guillaume Castroviejo

9 minute read
On 30 November 2022, Ofgem published its Final Determinations (FDs) for the RIIO-ED2 price control covering the electricity distribution (ED) sector for the next five years from April 2023 to…
8 minute read
To what extent is future success affected by past success? This topical question has implications for many areas of society, including education. However, a new study suggests that the answer…
16 minute read
Should companies be allowed to cooperate—or ‘collude’—on socially beneficial environmental behaviour? Do companies even have the incentive to cooperate on socially beneficial behaviour? In this article, we reconcile apparently divergent…

Navigating Merger Control

Together with Skadden and ThoughtLeaders4, Oxera is delighted to invite you to join us on Tuesday 4 June, along with senior members of the EU and UK judiciary and competition authorities, to discuss the current complexities in navigating merger control. Click here to register for the… Read More

Image depicting Navigating Merger Control

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