This Practice Note explains underground banking, its history, current usage and associated risks. It is aimed particularly at law firms caught by the Money Laundering, Terrorist Financing and Transfer of Funds (Information on the Payer) Regulations 2017 (MLR 2017), SI 2017/692 and the associated requirements to identify and assess risk, maintain policies, controls and procedures to manage those risks and report activity giving rise to suspicion of money laundering or terrorist financing.