Tax consulting firms are, in an economic sense, ordinary businesses, for which the generally accepted principles of proper business valuation should be applied. Tanja Winter provides an overview of the fundamentals of business valuation, focusing particularly on valuation occasions and the various valuation theories. The emphasis of her study is on determining the business value of a tax consulting firm. Based on the substance value and earnings value methods, she demonstrates how a decision value can be determined in the context of a sale or acquisition and analyzes the application of the discounted cash flow method for valuing tax consulting firms. She examines the industry-specific valuation methods and specifies them based on the recommendations and guidelines of the Federal Chamber of Tax Advisors.