I very strongly believe you to be wrong:
1. Unrealized gains is unworkable. Billionaires will spend tens or hundreds of millions yearly to avoid paying literally billions in taxes because the expected value is net positive. The IRS won't win chasing down money scattered across the globe. This is not a productive use of capital.
2. Taxing unrealized gains causes extreme capital flight. This is _bad_ for the US.
3. Taxing unrealized gains will lead to corporations and startups incorporating outside the US and keeping their assets outside of the US. This is _bad_ for the US.
4. Founders would very quickly loose control of the companies they started, including before they exit. That is really bad for startups and the ecosystem.
5. This is almost certainly illegal in the US at the federal level.
6. Every tax for the wealthy eventually targets the middle class.
2. Where will the capital go (all the best investments are in the US), if this happens lots of great businesses will be available to buy at a discount to people with smaller than $100m stock portfolios
3. Potentially true but I would still set up my business in the US and just pay the tax, if I make $100m it’s $20m for the government and I rate that as a great deal to be honest.
4. Why is a one off 20% tax going to lose founders control, this is only about companies post IPO.
5. IANAL are you?
6. If the rich continue to be able to accumulate wealth without paying taxes on it forever I think that is the road to serfdom personally. Taxation of the rich will make everyone better off. I pay over 50% tax in Europe, maybe if the rich were paying their share this could be reduced!
You've described the wrong type of tax. I make $100m and 20% goes to the government is not controversial. It's my business is valued at $100m and so I pay $20m to the government regardless of how much my company is "making".
> 4. Why is a one off 20% tax going to lose founders control, this is only about companies post IPO.
Got it. So no more IPOs and every public company is about to go private.