Brattle economists advised a large European energy company and a large financial institution throughout investigations of competition conducted by the UK Competition and Markets Authority (CMA) during 2014 to 2016. We worked in partnership with the client and their legal counsel in responding to CMA assessments of competition, including assessments of unilateral and coordinated market power; reviewing companies’ pricing strategies; reviewing analysis of consumer switching behavior and gains from switching; and, for energy, responding to the CMA’s assessments of costs and profitability in generation and supply comprising detailed margin analysis.