# Evaluating Annuities, Pensions, and Social Security – SWR Series Part 56

February 6, 2023 – Welcome to another installment of my Safe Withdrawal Rate Series. See the landing page of this series here for an intro and a summary of all the posts I’ve written so far. On the menu today is an issue that will impact most retirees: we all likely receive supplemental cash flows in retirement, such as corporate or government pensions, Social Security, etc. Some retirees opt for an annuity, i.e., transform part of their assets into a guaranteed, lifelong cash flow.

Of course, if you are a long-time reader of my blog and my SWR series you may wonder why I would write a new post about this. In my SWR simulation toolkit (see Part 28), there is a feature that allows you to model those supplemental cash flows and study how they would impact your safe withdrawal rate calculations. True, but there are still plenty of unanswered questions. For example, how do I evaluate and weigh the pros and cons of different options, like starting Social Security at age 62 vs. 67 vs. 70 or receiving a pension vs. a lump sum?

Also, you might want to perform those calculations separately from the safe withdrawal rate analysis, from a purely actuarial point of view. For example, we may want to calculate net present values (NPVs) and/or internal rates of returns (IRRs) of the different options before us. Clearly, NPV and IRR calculations are relatively simple, especially with the help of Excel and its built-in functions (NPV, PV, RATE, IRR, XIRR etc.). However, the uncertain lifespan over which you will receive benefits complicates the NPV and IRR calculations. How do we factor an uncertain lifespan into the NPV calculations? Should I just calculate the NPV of the cash flows up to an estimate of my life expectancy? Unfortunately, the actuarially correct way is more complicated. But Big ERN to the rescue, I have another Google Sheet to help with that, and I share that free tool with you.

Let’s take a look…

Continue reading “Evaluating Annuities, Pensions, and Social Security – SWR Series Part 56”