»The Registered Association in Professional Football – Failure of Legal Form, Secondary Purpose Privilege and Questions of Attribution«: The thesis examines whether professional football clubs are committing a breach of legal form due to their commercial business operations in the form of the professional players' section. Particular attention is paid to BGHZ 215, 69 (= NJW 2017, 1943 ff.) and the extent to which a spin-off of the licensed players' section counteracts the legal form violation. In addition, a proposed solution for a legally compliant organisation of the club's own professional players' section is presented.