A single premium immediate annuity is an annuity in its simplest form--it converts a sum of money into a stream of payments that are guaranteed for life. A single premium immediate annuity (SPIA) is sometimes referred to as an immediate annuity or a life annuity. A SPIA provides guaranteed payments to you (or you and a spouse if you are married) as long as you live. The amount that you use to purchase the annuity is transferred to the insurance company in a single, lump-sum payment. A single premium immediate annuity is relatively inexpensive (in terms of fees) when compared to other annuity types, and although this annuity type is straightforward, it is powerful and preferred by many financial advisors and economists. With a single premium immediate annuity: 1) the money goes in as a lump sum; 2) the money can be invested at a fixed or variable rate, and; 3) payments start right away and can be fixed or variable.