So, you take the cash option of $930 Million. What do you do now?
Let’s say you want to put some into a business, some into investment (including say buying your own tropic island). After taxes state and federal you will have approximately $490 Million left. So, let’s say you invest $400 Million. Assume an average 5% return on investment. At the end of 20 years you’d have $660 Million to play with after taxes.

If instead you took the money and put 1/2 into a Foundation that you controlled, the other half kept, you’d have about $245,000,000 left to invest, etc. However, if you were planning on giving to charity anyway, this allows you to use the money for charitable purposes and it grows tax free which allows more money to go to charity than using aftertax money to make gifts later. At the end of 20 years assuming a modest 5% growth rate, the charitable funds would be worth approximately $930 Million. The $245 Million which you’ve invested would be worth about $392 Million due to taxes on your investment income.

The moral is that if you are charitably minded do it at the beginning. That way, you have instead of $660,000 to give away over time, you have $1.17 Billion to control and of that $930,000 is available to charity.