Judgment of the General Court (Fourth Chamber, Extended Composition) of 17 May 2023.#EVH GmbH v European Commission.#Competition – Concentrations – German electricity market – Decision declaring the concentration compatible with the internal market – Action for annulment – Locus Standi – Admissibility – Duty to state reasons – Concept of ‘single concentration’ – Right to effective judicial protection – Right to be heard – Definition of the market – Period of analysis – Analysis of market power – Decisive influence – Manifest errors of assessment – Duty of care.#Case T-312/20.