[AnimalMuppet]

Hmm. Maybe use a log scale? Every factor of 10 in income, the incremental tax rate goes up a percent or three. If 35% is the top now, and starts at $100K (numbers made up because I refuse to grovel through the IRS code in order to make an HN post), and if the delta is 3% per factor of 10, then we get 38% at $1M, 41% at $10M, 44% at $100M, 47% at $1B (income, per year). I'll stop there, because I'm not sure anyone has ever reported $10B income in one year ever in history.

If you made the delta 9%, that would get you 44% at $1M, 53% at 10M, 62% at $100M, and 71% at $1B. This gets you in the neighborhood of Ocasio-Cortez's idea, but without one big step to get you there. (I suspect that it would also raise considerably less money than her plan...)

[tracker1]

The problem is that enough types of activity are excluded from taxation. It would be better to have a 0.25% margin tax on all financial transactions or currency transfers. Nobody could avoid it, and some of the micro-trades wouldn't happen as much.

Yes, then you still have the cash loophole, but most people aren't using cash.