WKBT January 6, 2021 11:46 AM David Rodeck - Forbes Advisor Posted: Updated: January 8, 2021 5:43 AM A single premium immediate annuity (SPIA) is one of the simplest types of annuity contracts. With a SPIA, you make a single large deposit with an annuity company and your monthly payments begin immediately. While SPIAs are easy to understand, buying them requires some foresight. You purchase a SPIA with a single lump sum, instead of making incremental payments over time as with some other types of annuities. What Is a Single Premium Immediate Annuity? A single premium immediate annuity is an annuity purchased with one large upfront payment. The SPIA immediately begins paying you back your purchase price plus a modest interest rate in installments.