Citizenship of the United States
A person who is considered a citizen by more than one nation has "dual citizenship". It is possible for a United States citizen to have dual citizenship; this can be achieved in various ways, such as by birth in the United States to a parent who is a citizen of a foreign country (or in certain circumstances the foreign nationality may be transmitted even by a grandparent) by birth in another country to a parent(s) who is/are a United States citizen/s, or by having parents who are citizens of different countries. Anyone who becomes a naturalized U.S. citizen is required to renounce any prior "allegiance" to other countries during the naturalization ceremony; however, this renunciation of allegiance renunciation of citizenship to those countries.
Royal Bank of Canada
On January 15, 2007, CBC Radio reported RBC is "refusing" people of certain nationalities to open U.S. dollar accounts with the bank. Canadian citizens with dual citizenship in Cuba, Iran, Iraq, Myanmar, North Korea or Sudan (mostly countries with U.S. sanctions) are affected. The U.S. Treasury Department restricts certain foreign nationals from using the U.S. dollar payment system to limit terrorism and money laundering after the September 11, 2001, attacks. RBC replied that compliance with such laws does not represent an endorsement by the bank and on January 17, clarified its position on the application of the U.S. laws, specifying that "with some exceptions" it does open accounts for dual citizens of the sanctioned countries. There have also been reports that the bank has closed the accounts of some Iranian-Canadian citizens.