Why would that be? If an asset has a certain RoI people will want to own it.
So who is going to buy the existing investor's wealth? Are they just going to buy each other's wealth?
Another example is McKenzie Scott selling billions in Amazon stock. There's no shortage of buyers for that.
Why would they buy?! You're saying it as if the market-wide sale of a share of every billionaire's stocks that year would just be absorbed by the market without any negative economic consequences (at best) or without a massive economic crash.
> Another example is McKenzie Scott selling billions in Amazon stock. There's no shortage of buyers for that.
That wouldn't be the case if every "McKenzie Scott" is selling billions worth of stocks simultaneously. There would certainly be a shortage of buyers.
I suspect these two things will happen on the market:
1. You'd need to have a wealthy enough buyer for the assets - it's going to be kinda hard to convince the wealthy to buy back their own assets. 2. In the absence of sufficiently large market makers, the prices of these assets will certainly tank since these assets will have to be liquidated.
So where is the government going to find the buyers of the assets? What are the economic effects?
Well, we can look to Switzerland for that answer. It is one of the only countries that have wealth taxes, but it's on the canton level (the equivalent of the state level). It has no national wealth taxes. The difference in wealth tax rates makes a huge impact on the behavior of citizens and the wealth distribution:
"According to our baseline estimate, a 1 percentage point drop in the top wealth tax rate raises reported wealth by 43%." https://voxeu.org/article/wealth-taxation-swiss-experience
"The evaluations with both datasets lead to similar estimates: an increase in the wealth tax rate by one tenth of a percent, whether this be at the cantonal or municipal level, reduces the amount of declared wealth by around 3%. This implies that the tax elasticity of wealth is at least twice as large as that of personal income.4 In other words, wealth reacts more sensitively to taxes. Our estimates also exceed the wealth tax elasticities of other studies, which is presumably due to the higher quality of the data available to us (panel data) (Seim 2017; Zoutman 2015)." https://www.ifo.de/DocDL/dice-report-2018-2-bruelhart-schmid...
In essence, it second article highlights your point: the behavior isn't changed much in terms of productivity because wealthy people simply hire competent accountants to minimize their wealth tax burden with better accounting structures.
BTW, we do have a wealth tax in the US in terms of private property. Most states have private property taxes which are a form of wealth tax. The effect of that is that each person has to generate an income high enough to afford the tax or else they will get a lien on their assets.