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.

Before joining Oxera, he obtained 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.

He advises regulated companies in the water, energy, and aviation sectors in their interactions with the regulator, including supporting them in assessing their cost efficiency through various quantitative benchmarking methods. He regularly provides strategic advice to investors or regulated operators.

Guillaume also has significant experience in due diligence exercises and merger procedures involving regulated entities.

Guillaume speaks English, and French.

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

Guillaume's specialisms include:

Selected
professional experience

  • Impact assessment of a merger between several electricty distribution network operators (2024–)

  • Economic study of the interdependence between aeronautical and commercial activities on behalf of a European airport (2024–)

  • Development of a series of recommendations as part of Oxera’s response to Ofwat’s public consultation on its approach to assessing mergers (2024–25)

  • Provided advice to a water company in formulating its response to cost assessment in Ofwat’s PR24 draft determinations—contributing towards achievement of a substantially better outcome at final determination stage (2024)

  • Due diligence advice in relation to the recapitalisation of Thames Water, the largest water and sewerage company in England and Wales (2024)

  • Independent review of the effectiveness and incentives of the legislative and regulatory frameworks applicable to large French airports, including providing regulatory and strategic advice to a key stakeholder (2023–24)

Qualifications

  • 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

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RIIO-ED2 Final Determinations

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When to give the green light to green agreements

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…

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