of National Firms. In this thesis, the author departs from neoclassical theory and opens up a new area of international production. At first, Hymer started analyzing neoclassical theory and financial investment, where the main reason for capital movement is the difference in interest rates. After this analysis, Hymer analyzed the characteristics of foreign investment by large companies for production and direct business purposes, calling this Foreign Direct Investment (FDI). By analyzing the two types of investments, Hymer distinguished financial investment from direct investment. The main distinguishing feature was control. Portfolio investment is a more passive approach, and the main purpose is financial gain, whereas in foreign direct investment a firm has control over the operations abroad. So, the traditional theory of investment based on differential interest rates does not explain the motivations for FDI. According to Hymer, there are two main determinants of FDI; where an imperfect market structure is the key element. The first is the firm-specific advantages which are developed at the specific companies home country and, profitably, used in the foreign country. The second determinant is the removal of control where Hymer wrote: "When firms are interconnected, they compete in selling in the same market or one of the firms may sell to the other," and because of this "it may be profitable to substitute centralized decision-making for decentralized decision-making". Hymer's second phase is his neoclassical article in 1968 that includes a theory of internationalization and explains the direction of growth of the international expansion of firms. In a later stage, Hymer went to a more Marxist approach where he explains that MNC as agents of an international capitalist system causing conflict and contradictions, causing among other things inequality and poverty in the world. Hymer is the "father of the theory of MNEs", and explains the motivations for companies doing direct business abroad. Among modern economic theories of multinationals and foreign direct investment are internalization theory and John Dunning's OLI paradigm (standing for ownership, location and internationalization). Dunning was widely known for his research in economics of international direct investment and the multinational enterprise. His OLI paradigm, in particular, remains as the predominant theoretical contribution to study international business topics. Hymer and Dunning are considered founders of international business as a specialist field of study. Physical and social factors of competitive business and social environment The conduct of international operations depends on a company's objectives and the