Starting from the functional concept of foundations developed by Andreas Schlüter, this work presents a comparison of legal forms in the first part, examining the legal foundation, the non-independent foundation, and the foundation corporation. It also provides design suggestions for aligning the alternative forms with the legal foundation. In the second part of the work, the functional concept of foundations serves as a model to discuss issues such as the fundamental rights protection of the founder, the endowment for specific purposes of the recipient foundation, the asset binding in the event of dissolution or change of legal form of the foundation, as well as the treatment of foundation corporations in nonprofit law.