And once the asset is sold, that's a taxable event.
1. Assumes the asset in question is publicly traded.
2. Assumes the publicly traded asset has a non trivial amount of trade volume 3. Assumes asset price is relatively stable, moving in a narrow band along a clear trend-line
4. Assumes you have defined the price from the stock information (last trade before close. Daily average, etc)
5. Assumes holder's position is small enough not to affect stock price were they to sell.
And stocks are the easiest to do this with!
Look at the Trump vs NY court case for the value of his house in FL. Unlike the valuation imposed by government fiat, the valuation was agreed to freely by the parties. The courts found it excessive (and it might be) and proposed a valuation so ridiculously low it alone gives Trump grounds to appeal that the judge is either incompetent on the matter or has a personal bias and should anyway have recused himself.
Are we talking about Mar-a-Lago here?
> the valuation was agreed to freely by the parties
Which valuation is that? The one from Lawrence Moens?
The banks agreed to the valuation and under no coercion agreed to lend money with it as collateral. Trump pays off that loan and the banks are made whole.
By contrast my school board telling me my house is worth 600 k instead of 400 k scares the shit out of me. I can't agree to it and my only recourse are the courts. The school board has lawyers on staff so it costs them nothing if I sue.