This diploma thesis deals with the issues of raising capital and capital maintenance from credit unions. The legal problem arises mainly related to the new requirements of the Basel Committee on Banking Supervision (Basel III). At the beginning, a brief introduction to the Austrian banking sector is given. After the statutory definition, the key principles of co-operative banks are explained shortly. Subsequently, the central Raising capital instruments and capital preservation instruments on the basis of the current law are in the centre of the diploma thesis. Then, after the processing of current relevant legal regulations, additional information on the central legal issues in the adaptation of these instruments in relation to the new requirements of Basel III is offered. Finally, an overview and a personal outlook on the major problem areas and viable solutions are discussed.