Basically if you earn a certain amount or have a high enough net worth, you must pay a tax on all of your assets as if you were selling everything you owned. You are charged this amount even if you are not selling anything.
This is the only wealth tax in America as far as I understand it.
Esther Jenke also told the Times that finances played a role in her decision to renounce her citizenship.
"My husband and I bought a house. If we sell the house, even though it is our primary residence, because from a US perspective it's foreign property, we would have to pay capital gains tax on it," Jenke told the Times.
The 1st part says that there is a financial reason to renounce your citizenship, but the 2nd part makes it seem like they'll pay capital gains on the house, specifically because they renounced their citizenship