More than 173,000 banking institutions from most countries around the world have decided to comply with the FATCA (Foreign Account Tax Compliance Act). At the time of writing, 167 Greek banking institutions have signed up to FATCA.

FATCA-compliant banking institutions are required to track bank accounts of US citizens, whether they live in the US or abroad, and report the details of those accounts to the US tax authorities. Banks are required to check for evidence of US citizenship/tax residency, such as whether a US passport was presented, whether any document lists the US as the place of birth, whether there is a US address, and whether there are instructions for wire transfers from foreign banks to US bank accounts.

So, for example, a Greek citizen born in the US who maintains a bank account in a Greek bank, under FATCA, will have to fill out a form with his or her details which will be electronically disclosed to the US authorities. Any refusal to fill in the form with his details may result in the account being frozen.

Of course, this means that US citizens in Greece who have not complied with their tax obligations to the US will have to do so immediately.