You&#x27;re a permanent resident until you formally renounce permanent residency at a US embassy or consulate. Some may permit mailing in your green card, others require you to appear in person. However, the process is or was free when I went through it.<p>I think there are other ways of losing permanent residence, but the only guaranteed ways are when you renounce or when the US takes it from you. Either way, you better have written proof.<p>If you&#x27;re a long-term permanent resident (8 years or more), then you&#x27;re subject to the same expatriation tax rules as US citizens. The IRS agents that I spoke to were all friendly and helpful, but unfortunately none of them knew the expatriation rules. It wasn&#x27;t as bad as it may sound, but it wasn&#x27;t fun either.<p>You also have to file a preliminary tax return before you actually leave the country (informally called the sailing permit).<p>Anyway, just leaving the US isn&#x27;t good enough when you&#x27;re a permanent resident and until you&#x27;re through the process you&#x27;re on the hook. And don&#x27;t forget to meet FACTA requirements for the year in which you gave up PR...