Final answer:
When receiving cash in excess of $10,000 from one customer in one business day, a firm is required to file a Currency Transaction Report (CTR) with FinCEN.
Step-by-step explanation:
When a firm receives cash in excess of $10,000 from one customer in one business day, they are required to file a Currency Transaction Report (CTR) with the Financial Crimes Enforcement Network (FinCEN). This report is used to identify any potential money laundering or illicit activities. By filing a CTR, the firm is ensuring compliance with anti-money laundering regulations and helping to maintain the integrity of the financial system.