How are you going to keep a running total? Realistically, how? Much wealth is not publicly known, especially given international holdings. No one knows how much money Putin has, for example.

And then you have the more basic issue that private companies don’t have a known true value. They have a book value for the real property they hold (real estate, buildings, equipment, inventory, furniture, vehicles, etc) but many companies have a potential value far in excess of that due to technology. That value can’t really be calculated until the business goes public or is sold.

So what you end up with is people will just give their friends and family shares in their private company, valued at a very low number, then later when they go public they can all go up to $999m before selling out.

The thing to realize about billionaires is that they have so much money they can hire an entire accounting department to circumvent basically any simple tax law you come up with.

Except land value taxes. Land can’t be moved and the land value is assessed based on the neighbourhood, not on any information the owner might hold secret, so there’s no way to avoid land value taxes if you want to own land.