Variable immediate annuity is not guaranteed because with this option you can put some of your money in a fixed income option and a part can go in a investment option, where professionals manage your money by investing in stocks and bonds. The variable immediate annuity could be risky because, though it provides you with a potential of more income than the fixed income option, your income may go down if the market is down or based on the performance of the stocks or bonds that your money is invested in.