Any bank or financial institution in the UK which has a US operation must, under the FATCA rules, review their customers' tax information or be subject to a 30 per cent penalty tax applied to their US operations.

The Inter-Governmental Agreement (IGA) with ​the UK is sometimes known as UK FATCA. This is because the information exchanged under the UK IGA is similar to that exchanged with the US under FATCA. It's sometimes referred to as CDOT (crown dependencies and overseas territories).

UK FATCA. In order to minimise compliance costs for financial institutions, UK IGAs follow FATCA closely. Where there are reciprocal IGAs, identification of the partner jurisdiction is required in order to establish taxability; this contrasts with the US requirement, which taxes US citizens, wherever resident.

There are currently 87 countries with active FATCA agreements with the U.S. These include: Algeria, Angola, Antigua and Barbuda, Australia, Austria, Azerbaijan, the Bahamas, Bahrain, Barbados, Belarus, Belgium, Bermuda, Brazil, the British Virgin Islands, Bulgaria, Cambodia, Canada, the Cayman Islands, Colombia, ...

When you open a new bank account for your group, the bank may send you a form called something like “CRS Entity Self-certification form” or “Tax Residency Self-certification Declaration form”. The form may mention something called the Common Reporting Standard or Automatic Exchange of Information.

FATCA requires foreign financial institutions (FFIs) to report to the IRS information about financial accounts held by U.S. taxpayers, or by foreign entities in which U.S. taxpayers hold a substantial ownership interest.

FATCA generally requires Americans to report all their foreign assets when filing their taxes. However, there are some types of assets that are exempt from this requirement—including real estate located in the United States and certain retirement plans meaning that some expats have FATCA exemption.