A company hired by lenders to recover funds that are past due or accounts that are in default. The lending company itself may also have a division or subsidiary that acts as its collection agency. A collection agency is often hired after a company has made multiple attempts to collect its receivables. At some point in time, every business that sells on credit or a medical practice, is going to have a collection issue. Some customer, client or patient, for whatever reason, is not going to pay your invoice or bill on time. This is when you need to leverage the 'fear factor' and consider hiring a third party collection agency.