Both MIS and FD have similar investments and are popular investment options. However, the choice between the two depends on your investment goals and risk appetite. Currently, Post Office MIS offers an interest rate of 7.4% whereas FD interest rate could go up to 8%. Also, FDs come with a tenure of 7 - 10 years, whereas POMIS comes with a lock-in period of 5 years. FD interest rates are slightly prone towards market fluctuations compared to MIS. Consider all these factors before investing in either of the investment vehicles.