Q. How do I determine the annual interest rate — not the payout rate — I am earning on a single premium immediate annuity (SPIA)? It seems there is no simple way to determine how to do it. Also, is this a good time to purchase a SPIA since it is partly determined by long-term bond rates and not affected by the Fed’s short term interest rate hikes? — Unsure A. There’s a lot to unpack here. You need to make a few calls. To determine the annual interest rate for a single premium immediate annuity (SPIA), you should start by speaking to the insurance agent who sold you the product, said Marc Alan …