The Financial Crimes Enforcement Network (FinCEN) is a bureau of the United States Department of the Treasury that collects and analyzes information about financial transactions in order to combat domestic and international money laundering, terrorist financing, and other financial crimes.
A currency transaction report (CTR) is a report that U.S. financial institutions are required to file with FinCEN for each deposit, withdrawal, exchange of currency, or other payment or transfer, by, through, or to the financial institution which involves a transaction in currency of more than $10,000. Multiple currency transactions must be aggregated, and a CTR is required, if the financial institution knows or has reason to know that the multiple transactions are by or on behalf of any person and result in either cash-in or cash-out totaling more than $10,000 in one business day.