(and contra Graham, it's only assessed at a per-mille level, not percents)
Also, at that point, you shure as hell diversify your assets, instead of having them all in a single privately held company.
That's why we need a transaction tax on stock combined with tax breaks on stocks that have societal value, together with a ban on all derivatives. Stock markets need to be first order long term srategy crowdfunding again like they were originally invented as. Otherwise computers will just chase the next peofitable microsecond and CEOs will juse try to optimise the next quarter.
I know how real estate and tangible/intangible asset values are assessed for property taxes purposes, and the problems with that are enormous, not to mention the avenues for fraud and increased paperwork. There are definitely winners and losers there based on your level of influence in society.
How and who determines what “stocks” have societal value?
It’s really easy to say these things, but I have yet to come across someone with even a half baked plan to implement them in a fair way. For example, currently startup employees get screwed with the way taxes work on options, where they owe significant taxes for nebulous gains that they may or may not benefit from.
If it makes it clearer, suppose the market value of the assets you own increases from $10M to $15M in a year. How would you tax this? Do you start forcing people to sell? What if the asset they own isn’t publicly traded, for example land, or privately owned companies?
It’s not a “gotcha I’m against increasing taxes on wealthier people statement”. It’s a legitimate question on how to operate society when do much of the wealth is simply from increasing asset prices and decreasing currency values.