More than 173,000 financial institutions from most countries worldwide have decided to comply with FATCA (Foreign Account Tax Compliance Act). Financial institutions that comply with FATCA are required to identify bank accounts held by U.S. citizens, whether they live in the U.S. or abroad, and report the details of those accounts to U.S. tax authorities. Banks must look for indications of American citizenship or tax residency, such as the presentation of a U.S. passport, listing the U.S. as the place of birth on any document, having a U.S. address, or instructions for wire transfers from foreign banks to U.S. bank accounts.

For example, an EU citizen born in the U.S. who maintains a bank account in a European bank, according to FATCA, must complete a form with their information, which will be electronically disclosed to U.S. authorities. Refusal to complete the form may result in the freezing of the account.

Of course, this means that American citizens abroad who have not complied with their U.S. tax obligations must do so promptly.