FDI stands for Foreign Direct Investment whereas FII stands for Foreign Institutional Investor. So just from the name we can tell that FDI has to do with investing in something, whereas FII is an institution looking to make an investment or has already made an investment. Now to address your second question, FDIs are investments in something tangible such as power plants, roads, bridges, real estate. However, PNs were geared towards investments in stocks and therefore is much more liquid investment and therefore not the same type of investment as an FDI.
