Depositing exactly $10,000 in physical cash into a bank account initiates mandatory federal reporting protocols designed to track large cash movements and deter financial crimes. Under the Bank Secrecy Act, financial institutions are legally required to record the transaction details and file a Currency Transaction Report with federal regulatory authorities when physical cash transactions meet or exceed the $10,000 threshold. The bank teller will request your government-issued identification to verify your identity. This administrative filing is standard practice for large cash movements and does not indicate unlawful activity, provided the funds are acquired legally. However, breaking a cash sum into smaller amounts to deliberately dodge this rule constitutes illegal structuring.