Judgment of the Court (Grand Chamber) of 11 December 2018.#Proceedings brought by Heinrich Weiss and Others.#Request for a preliminary ruling from the Bundesverfassungsgericht.#Reference for a preliminary ruling — Economic and monetary policy –– Decision (EU) 2015/774 of the European Central Bank — Validity — Secondary markets public sector asset purchase programme — Articles 119 and 127 TFEU — Powers of the ECB and the European System of Central Banks — Maintenance of price stability — Proportionality — Article 123 TFEU — Prohibition of monetary financing of Member States in the euro area.#Case C-493/17.