Earlier quoted context omitted.
> The dollar value of shares tend to increase over time, a basic fact not reflected in this model. This is not reflected in the model because the price of the shares cancels out: a higher price means a higher tax in absolute dollars, and a lower price means a lower dollar amount in tax. For a given tax rate you end up with the same fraction of the shares regardless of any appreciation or depreciation in their value.…
You can take a loan on your shares to pay for the tax, which happens all the time for most expenses.
It does bring up an interesting point, however. Is this tax applied to net wealth? Can you subtract money that you owe to someone else? What if the lender is outside the country and thus not subject to the wealth tax? And what happens if your net wealth is negative—do you get a refund?