[a3n]

OK, all but mandatory. But I believe the USG will not recognize your renunciation until you've paid all your back taxes.

[OneOneOneOne]

That's not all. I think you have to pay an additional fee if your assets are >2M...

https://www.washingtonpost.com/business/economy/youd-have-to...

I'm not planning on leaving or have assets in the range. It seems like kind of a ripoff though.