Final answer:
A Currency Transaction Report must be filed for cash transactions exceeding $10,000 by a single customer in one business day. This is to prevent money laundering and is required under the Bank Secrecy Act.
Step-by-step explanation:
A Currency Transaction Report (CTR) must be filed for all cash transactions by a single customer during a single business day that exceed $10,000. This is a requirement set by the Financial Crimes Enforcement Network (FinCEN) under the Bank Secrecy Act (BSA) to help prevent money laundering and other financial crimes. Financial institutions must file CTRs electronically through the BSA e-filing system. Multiple transactions that total in excess of $10,000 and are conducted by or on behalf of the same person must also be reported in a CTR.