This work comprehensively addresses the controversial topic of co-partner liability for asset-related claims of a partner in a partnership, who acts as a creditor towards their company, through an in-depth analysis of case law and literature. Regarding the third-party creditor claims that are primarily examined, the author argues for deriving the scope and nature of co-partner liability for claims established by the third-party creditor-partner fundamentally from the protective function of partner liability, taking an economic perspective. He also advocates for distinguishing this situation both doctrinally and in terms of value from the one in which an existing claim is transferred to a partner subject to external liability.