Judgment of the Court (Fourth Chamber) of 16 January 2025.#Banco Santander SA v Asociación de Consumidores y Usuarios de Servicios Generales-Auge.#Request for a preliminary ruling from the Tribunal Supremo.#Reference for a preliminary ruling – Markets in financial instruments – Directive 2004/39/EC – Article 52(2) – Action brought in the interests of consumers – Consumer organisations having a legitimate interest in protecting consumers – Standing to bring legal proceedings to defend the individual interests of their members – Loss of standing in the case of investments in high-value financial products – Exemption from court fees and from the obligation to pay the costs incurred by the opposing party – Procedural autonomy – Principle of effectiveness.#Case C-346/23.