The Bank Secrecy Act authorizes Treasury to require financial institutions and individuals to keep records and file reports that the Treasury determines have a high degree of usefulness in criminal, tax, or regulatory matters, or to protect against international terrorism. The information collected assist Federal, State, and local law enforcement in the identification, investigation, and prosecution of individuals involved in a variety of financial crimes.
The latest form for Reports of Foreign Financial Accounts Regulations and FinCEN Form 114, Report of Foreign Bank and Financial Accounts (FBAR) expires 2021-01-31 and can be found here.