Lottery winners of this magnitude will find themselves in the highest Federal tax bracket no matter whether they take the lump-sum or 29-year annuity. However, state income taxes vary widely across the country. I reside in a state with a marginal income tax rate of 6-7% at the highest bracket. If I took the lump-sum, I would pay that state tax on the full payment. If I took the annuity, I potentially have the ability to move to a low income tax state after receiving and paying tax on the initial payment.
How would I approach the decision?
First, let's ignore taxes and estimate the expected IRR of the annuity decision.
Option 1: Take the $480 million today
Option 2: Take the $758.7 million as a 30-installment annuity = $25.29 million/year
To estimate the IRR of the annuity using a business calculator, assuming you have the default settings that payments occur at the end of the year:
[FV] = 0
[PMT] = $25.29
[N] = 29 (the first payment is upfront today)
[PV] = -(480.0 - 25.29) = -454.71 (first payment is today)
[CPT] [I/Y] = 3.52%
So, the question to ask is whether 3.52% is adequate return in the current market environment for you. While this is not a "risk-free" annuity, lotteries are required to escrow the funds to guarantee future payments of the annuities, so theoretically, this is a low-risk investment.
The current yield on the 30-year treasury bond is 2.75%. One would need to consider whether the 77 basis points is adequate return to compensate for the level of risk present in the future payments.
For me, personally, I would lean toward taking the annuity. However, I would also shop around to see whether I could buy a better annuity in the market place that replicates even higher payments for the $454.71 million investment. You may have trouble finding an annuity company to take that much money from you, or a company that you trust will be around for 29 years though.
Now, about those taxes that we ignored. The ability to move residency to a low income tax state such as AZ or FL gives an added benefit of the annuity option for me personally, as I live in a moderately high income tax state. However, we also have to think about expectations for future Federal tax rates. Given the massive $19.97 trillion US government debt, do you think that future tax rates over the next 29 years will on average need to be higher or lower than they are currently? If you think Federal tax rates have to increase, then the lump-sum is the better option. If you think they stay roughly the same, then it is a wash. Lower future tax rates favor the annuity.
The other issue as others have noted is whether you can trust yourself to use the money wisely. It would be much easier in my opinion to manage the annuity payments than the big lump-sum. The annuity helps tie your hands a bit and keeps you from making stupid investment decisions, not to mention all of the leeches that will suddenly appear wanting a piece of the action.