You have 10 shares @ $100, they increase to $200.
You owe 20% of $1000, so $200.
So to get your money, you sell 1 share @ $200.
Oh wait, you got this share with a cost basis of $10, so now you owe capital gains on the same of the
one share for $190, capital gains is 15% or 23-24% depending on income, but lets go with the 15%, so
you owe about $30 now, leaving you with $170 to pay the $200. Better sell another share, pay more taxes.
As it has been described, this isn’t a problem.
It isn’t a tax, it’s a floor on the tax rate.
So selling shares to pay the tax won’t incur tax.
(the sale would incur tax, but then the unrealized gain tax also incurs a tax, and you’d pay only the higher of the two, not both)
And presumably the value at each unrealized tax assessment day resets your cost basis to that level, so you don’t pay it over and over again.
In that sense, it’s an entirely workable tax.
However many years it takes your portfolio to reach $100bn, when you get there it’s worth only $80bn, no matter what happened along the way.
And a lot of capital gains tax is already paid.
There is only one big problem: what happens when stock prices go down?
If it goes up year 1 and you pay the tax on unrealized gains, then the stock price goes down year 2, what happens?
Do they do a cash refund the tax on unrealized losses as they taxed the gain on unrealized profits?
Or merely a tax credit? Or nothing?
The latter two would be a problem.
If the stock does an Enron and goes to zero, you’d want to get all the tax back, and with some reason.
Otherwise, in effect you’re paying tax on profits you never made and never got to benefit from.
If they refund it every year, the tax seems reasonably fair and workable.
Then you get to the next biggest problems:
What the heck is something worth? I foresee a lot of very well remunerated lawyers arguing how poor their clients are. This is messy, but can be done.
And what do you do if it’s something you can’t sell part of? Restricted shares, or an indivisible asset?
Do you get a loan from the government to pay your tax, payable if/when the asset becomes liquid or you die?
A lot of these things are already done in a lot of places: it resembles what happens when you emigrate from a lot of countries.
All your assets are all taxed on departure as if you had sold them, though in many cases the tax is deferred till when you actually do so.
Jim