Final answer:
Portfolio investment entails a small, often short-term stake with no management control, whereas Foreign Direct Investment involves a larger stake with some level of managerial responsibility and a long-term focus.
Step-by-step explanation:
The difference between Foreign Direct Investment (FDI) and portfolio investment is that portfolio investment involves purchasing a relatively small stake in a company—typically less than ten percent—with no managerial control and often with a short-term focus. On the other hand, FDI implies buying more than ten percent of a company, which often comes with some level of managerial responsibility, reflecting a more long-term investment strategy. Furthermore, portfolio investments can be liquidated much faster than FDIs. For instance, selling bonds issued by the government of the United Kingdom can be done with just a phone call or a few computer clicks, whereas selling a company, such as an automobile parts manufacturer in the UK, can take weeks or even months to execute.