The United States and Eritrea are the only countries in the world to tax based on citizenship.

If you’re a US citizen living outside the United States, you still have yearly IRS tax filing obligations. These tax filing obligations can be an expensive annual hassle (even if you owe no tax). They may even result in double taxation. Fortunately, properly renouncing your US citizenship can provide a way out. The US and Eritrea were the only countries to double tax based on citizenship and not residency