Project work from 2010 in the field of Business Administration - Corporate Management, Management, Organization, Grade: 1.0, Administrative and Business Academy Essen, Language: German, Abstract: Based on the observation of real investor behavior, Markowitz laid the foundation for scientific research in the 1950s with modern portfolio theory (hereafter referred to as MPT) and significantly changed practical portfolio management. The core statement of Markowitz is: The risk of a securities portfolio does not correspond to the average value of its individual positions. He reduced the classical selection and decision-making problem in the choice of various assets to the first two statistical distribution parameters: risk and return. In this context, correlation was particularly highlighted, describing the synchronous and asynchronous movements of the pre-selected individual positions.