Judgment of the Court (First Chamber) of 4 October 2024.#thyssenkrupp AG v European Commission.#Appeal – Competition – Regulation (EC) No 139/2004 – Concentration between undertakings – Decision declaring the concentration incompatible with the internal market and the functioning of the EEA Agreement – Determination of the relevant markets – Significant impediment to effective competition – Creation or strengthening of a dominant position – Non-coordinated effects – Standard of proof – Concepts of ‘important competitive force’ and ‘close competitors’ – Closeness of competition between the merging parties – Herfindahl-Hirschman Index – Requests for information – Distortion.#Case C-581/22 P.