(to or from the US)
Immigrating to the US entails changing from nonresident tax status to US tax status. Planning for this change is important because it is generally possible to delay or accelerate the change date if the correct steps are taken at the right time. See Moving to the US?
Planning is even more important for prospective immigrants who own shares in non-US companies or have interests in foreign trusts. See Foreign Trust?
Relocation from the US and taking up residency in another country does not change a US citizen or green card holder’s US tax status. However, US tax status is terminated where US citizenship is renounced or US permanent residence formally abandoned. In certain circumstances an “exit tax” is levied based on wealth.