Dan Mitchell: The Economic Damage of Wealth Taxation.
Consider a large farm worth $50 million in the US. The owner of that farm makes roughly $500,000 annually in profit. Now, the government decides to levy a "modest" wealth tax of 2%. The owner of that farm would have to pay $1 million a year, every year, for that farm. That one "small" tax is double his annual income. If he doesn't have substantial savings, then he'll have to sell the farm. Of course, then the new owner will have to worry about the tax. Most likely, the property value will drop and a few workers will be fired to make the whole enterprise more efficient.
Smart rich people will see this atrocity coming from a mile away. They'll quietly move a significant amount of their money to outside of the US before the wealth tax hits. In other words, the negative consequences of the wealth tax will be seen before it even goes into effect.