All financial institutions must adhere to the Money Laundering Regulations 2003 and the recommendation given by the Financial Action Task Force and Joint Money Laundering Steering Group - this means banks and all other financial institutions are obliged to take active measures to counter the efforts of money launderers.I'm not suggesting for one minute that the cash you refer to is from any illicit means, but if paying �1,000 cash into your account each week is deemed to be "unusual activity" based on your history with your bank, it may well raise suspicion and prompt the bank to lodge a report with NCIS. A financial institution will not not raise their suspicion with you first, as it would be committing a criminal offence(known as "tipping off"). Of course, if the cash is from legitimate means, then you have nothing at all to be concerned about if your bank does become suspicous and NCIS are involved.