FATCA requires foreign banks to conduct due diligence to see if there are US persons with foreign bank accounts. The fact you did not give a foreign bank your US passport still does not mean they might not report your foreign bank, financial and other accounts to the US and IRS.

FATCA was enacted to expose those US citizens and green card holders who are trying various tricks such as dual passports, etc. to avoid reporting and paying taxes on their foreign financial accounts.

Under the FATCA law in order to stay in good graces of the IRS, the foreign banks must put into place procedures to weed out account holders who are Americans and US green card holders even though the passport they opened the account with said otherwise. These are the questions you need to ask yourself before you take the HUGH risk of not reporting those accounts on form TDF 90-22.1 (FBAR form).

Are there any US address associates with your account?
Are there any US phone numbers with your account?
Is your birthplace listed as somewhere in the US?
Have you made more than one wire in or out form the US?
Any other item that may make the bank suspicious you are a US person. Read More