The document discusses various theories that attempt to explain foreign direct investment (FDI). It categorizes the theories into those assuming perfect markets, imperfect markets, and those based on other factors. Theories assuming perfect markets include the differential rates of return hypothesis, diversification hypothesis, and market size hypothesis. Theories assuming imperfect markets include the industrial organization hypothesis, internalization hypothesis, location hypothesis, eclectic theory, product life cycle hypothesis, and oligopolistic reactions hypothesis. Other factors influencing FDI discussed include political risk, tax policies, trade barriers, and government regulations. The eclectic theory integrates several hypotheses and argues that FDI occurs when a firm has ownership advantages, internalization advantages, and locational advantages favor foreign