A paymaster often is, but is not required to be, a lawyer (also known as a 'lawyer paymaster'). When dealing with commission payments on contracts dealing with large amounts of money (such as Oil, Gas, Steel, Iron, Gold, MTN's, VG's, T-Strips, and other instruments), most banks in the United States are very wary of handling such large amounts of money. In addition, most buyers and sellers of such transactions want to place the money with a neutral third party for disbursement. In most cases it is required by the buyer and/or seller involved in the transaction that a paymaster be named to handle all incoming and outgoing funds.
This is where the paymaster comes in. A paymaster is typically a neutral third party (not directly involved with the transaction) who handles the incoming commissions, and then disburses the funds accordingly. In return for his services the paymaster charges a small fee, which is paid directly to him out of the commission proceeds prior to disbursement.
In the United States, there is no licensing requirement to be a paymaster. However, a paymaster often is a licensed lawyer, due to the security and safety issue that lawyers in the U.S. are required to hold any funds that do not belong directly to them in a "Attorney's Trust Account" (also known as an IOLTA account), which is monitored by the state bar, in the state in which the lawyer practices.