That family is already effectively paying a wealth tax in their local property tax bill every year on the home that they own," Davis said.
Once they're sold off, they're subject to the capital gains tax, which is much lower than the straightforward income tax most Americans pay on their paychecks.
If wealth over $30 million there was subject to a 2% wealth tax, it would bring in $88 billion.
According to the report, at the national level, a 2% wealth tax on those with over $30 million could bring in about $415 billion.
"We've seen a big rise in extreme wealth, partly because we tax that wealth so lightly, if at all," Davis said.