Joined Cases C-457/16 P and C-459/16 P to C-461/16 P: Judgment of the Court (Sixth Chamber) of 26 October 2017 — Global Steel Wire, SA (C-457/16 P), Trenzas y Cables de Acero PSC SL (C-459/16 P), Trefilerías Quijano SA (C-460/16 P), Moreda-Riviere Trefilerías SA (C-461/16 P) v European Commission (Appeal — Regulation (EC) No 1/2003 — Competition — Agreements, decisions and concerted practices — European prestressing steel market — Infringement of Article 101 TFEU — Attributability of unlawful conduct of subsidiaries to their parent company — Definition of ‘undertaking’ — Evidence for the finding of an economic unit — Presumption of actual exercise of decisive influence — Successive undertakings — Amount of the fine — Ability to pay — Conditions — Observance of the rights of the defence)