That is the 64 dollar question, but generally it is tax related and that the Expat has significant non-US income that requires a significant US tax bill, has little or no income and/or connection with the US and, of course, already have citizenship in another country.

On December 5, 2019 TaxConnections published our “Open Letter To Democrats Abroad” in which we argued that “revenue neutrality” should be irrelevant in moving from “citizenship-based taxation” to “residence-based taxation”. That post attracted a large number of comments from Americans abroad expressing the difficulties living under the citizenship-based taxation regime. The bottom line is that the United States is forcing expats to renounce their U.S. citizenship. Yes, its’ true. The comments reminded me of a post that appeared on my site in 2017. Settle in for the ride as you read the “13 Reasons Why …
Read full post: www.taxconnections.com/taxblog/13-reasons-why-i-committed-citizide-aka-renounced-my-us-citizenship/