The Court of Justice ruled that Malta’s 2020 investor citizenship scheme, which granted nationality in exchange for predetermined payments or investments without requiring a genuine link to Malta, violates EU law. While Member States retain competence over nationality matters, they must exercise it consistently with EU principles. Union citizenship is based on solidarity, good faith, and mutual trust between Member States. The commercialisation of nationality undermines these foundations, breaches the principle of sincere cooperation, and compromises the common area of freedom, security, and justice within the EU.