Judgment of the Court (Grand Chamber) of 6 October 2021.#Sumal, S.L. v Mercedes Benz Trucks España, S.L.#Reference for a preliminary ruling – Competition – Compensation for harm caused by a practice prohibited under Article 101(1) TFEU – Determination of the undertakings liable to provide compensation – Action for compensation directed against the subsidiary of a parent company and brought following a decision finding only that the parent company participated in a cartel – Concept of an ‘undertaking’ – Concept of ‘economic unit’.#Case C-882/19.