The aim of this bachelor thesis is to explain the Austrian terms of the Income Tax Act 1988 in more detail. The main focus of this work is placed on the sale of business, closing down and the non-essential transfer of an enterprise. A central point is the importance of the question of how to determine the capital gain. In this regard, attention is paid to the components of the divestment or to the duties of recovery and to the various methods of determining profits. In doing so, we pay more attention to the investigation methods of special taxed real estate and special taxed capital. The basic theory of realization gains is theoretically worked out with the help of various literature. As a last step, the fiscal effects of a sale of business, closing down and the non-essential transfer of an enterprise are listed, based on the Turnover Tax Act 1988.