Dex:
All in all I think you made an excellent report, but it appears to me that you’ve made an error that’s pretty common in these kinds of things.
To answer the question: Which should I take, the lump sum of the annuity, there are actually two factors at play. The first as you correctly state is the interest rate the assumption is based on.
The second factor is the discount rate.
The annuity calculation is a simplistic model used simply to compare interest rate assumptions between annuitties.
In a bond calculation the discount rate is figured in seperately, in an annuity calculation you must interpolate it.
For example, you say:
Me neither, but you really aren’t guarranteed to make 8.9% in terms of actual value to you, are you?
What you will actually receive is a sum in dollars equal to an 8.9% interest rate.
If inflation runs at 10% for the next 20 years, in terms of actual value you are actually losing 1.1% annually in real terms, are you not?
So, clearly if you accept the annuity and lock in for the next 20 years you are accepting inflation risk. As we all know, if we are accepting a risk, we must get paid for it, right? Therefore, we would expect something that exposes us to inflation risk to pay us more than something that did not (like cash in hand, which we can spend.)
Similarly, we are losing use of the money that will not be paid to us until a future time, and there is an opportunity cost.
Since we will be paid in dollars we will have currency risk
Since we will be locked into an interest rate assumption we will have interest rate risk.
Depending on how confident we are in the ability of the annuity to keep its promises for the next 20 years and actually pay us, we are taking credit risk.
Finally, we have the nebulous quantity that cash in hand is inherently more valuable than cash down the road, since it can be spent now against need, and is readily exchangeable into goods and services. In short it is liquid. Liquidity is valuable. Nothing is more liquid than cash in hand.
So, in order to make a good comparison we either need to step of the value of a present sum based on these factors, or discount the annuity to compensate for them.
There’s a number of ways we can do this.
One way to do it is to close your eyes, squint really hard, concentrate and try to give birth to a discount rate that compensates you realistically for these risks. I know some professionals that do just this. “All that crap, right now? 20 years? That’s a 4% discount rate!” (This works surprisingly well)
If we accept that than your real interest rate discounted for the risk you are taking is only paying 4.9%. Because a discount rate is the cost of the risk taken.
The other way to do is to assign all these risks an individual value, and add them up.
A third way to do it is to try and see what everybody else is doing. For example, the annuity payments versus a string of consecutive zero coupon treasuries, and you can seperate out credit risk and portion of liquidity risk (Treasuries are more liquid than the assignment of an annuity.)
Since we know the treasuries contain interest rate risk, inflation risk, and currency risk we are left with the relative difference in liquidities and credit qualities.
By far the biggest component of discounting an annuity is the almost total loss of liquidity due to the difficulty in disposing of the asset. Five years down the road should you have a major liquidity need and seek to cash it in for it’s present value, you will be sorely disapointed. Neither the insurance company, nor the state will want to hear it or be willing to accomodate you. You will have great difficulty in finding somebody willing to buy the annuity from you because of the assignment problems of such a vehicle and they will want to buy it only at a very steep discount to it’s current present value.
Typically, this liquidity is very very highly valued and not given up lightly. This is why so few annuities actually annuitize, and why so few immediate annuities are sold.
Conversely this is also why lotteries are paid in this fashion. Since they are disadvantageous on so many levels, they are the vehicle that expands the present value of a current sum of money at the greatest rate, enabling those running the lottery to present the largest possible prize for the least amount of money.
This is why a 20 year treasury pays so much less than the 8.9% you get if you accept the annuity.
You are giving up a lot to get that 8.9% and taking a lot of risk to do so with very little recouse.
This is why most advisors and planners will recommend the lump sum option to lottery winners and why almost all lottery winners take the lump sum option. Undiscounted, that 8.9% is an illusion.