Rebuild both numbers yourself
On Every holding, the two switches are these choices. With both off, the high end of our sum is $878.1B; with both on, it is $1.034T. That swing, $155.8B at today’s prices, is bigger than the whole gap between the two publishers, which tells you how much rests on these calls.
Why the gap moves every day
Both publishers value his listed shares at the latest close, so the shares themselves do not cause the gap. The disputed holdings do: the 2018 Tesla shares and the SpaceX options rise and fall with their share prices, so whichever publisher counts more of them pulls further ahead on a good day and drops further on a bad one.
Which one is right
Both are estimates of something nobody can measure exactly: he cannot sell most of his shares without moving their price, and the private companies have no price at all. That is why this site shows its sum as a range, says which choices make the ends, and dates every figure.