We reasoned as follows: The existing estate tax is a wealth tax levied at the time of death. If 2 percent of wealthy families experience a death and intergenerational transfer (rather than a spousal transfer) each year, then the current 40 percent estate tax should roughly be the equivalent of a wealth tax of 40 percent multiplied by 2 percent — or a 0.8 percent wealth tax — assuming equivalent definitions of wealth and the same threshold for taxation. Since most wealth is held by fairly elderly people, and the mortality rate of 70-year-olds is above 2 percent, we suspect that 2 percent mortality is a conservative estimate. So the actual wealth-tax equivalent of the estate tax is likely greater than 0.8 percent.
The IRS reports that for 2017, the most recent year for which data is available, the estate tax raised around $10 billion from estates over $50 million — and this included tax collected on the first $50 million of estate tax value, so it overestimates the conceptually appropriate figure. Therefore, if this is what the revenue yield would be from a 0.8 percent wealth tax, the implication is that a 2 percent wealth tax would raise a total of $25 billion. That’s around one-eighth of the Saez and Zucman estimate.
There is much more of interest at the link.