Sanders was on the right track when he ran.
https://berniesanders.com/issues/tax-extreme-wealth/
How the Tax on Extreme Wealth Would Work
This tax on extreme wealth would have a progressive rate structure that would only apply to the wealthiest 180,000 households in America who are in the top 0.1 percent.
It would start with a 1 percent tax on net worth above $32 million for a married couple. That means a married couple with $32.5 million would pay a wealth tax of just $5,000.
The tax rate would increase to 2 percent on net worth from $50 to $250 million, 3 percent from $250 to $500 million, 4 percent from $500 million to $1 billion, 5 percent from $1 to $2.5 billion, 6 percent from $2.5 to $5 billion, 7 percent from $5 to $10 billion, and 8 percent on wealth over $10 billion. These brackets are halved for singles.
Under this plan, the wealth of billionaires would be cut in half over 15 years which would substantially break up the concentration of wealth and power of this small privileged class.