$a is arbitrary. It doesn't matter how you arrived at it. As long as you provide a reasonable assessment to the IRS, pg's original point (which you objected to

$a is arbitrary. It doesn't matter how you arrived at it. As long as you provide a reasonable assessment to the IRS, pg's original point (which you objected to) is completely correct: an f% wealth tax is an f% seizure of your shares. And if you object that you can just lowball that assessment; well yes, and by the way you've just conceded nearly every point made by opponents of the wealth tax.