An agency trading desk (ATD) is a type of digital advertising platform that is managed by an advertising agency on behalf of its clients. The ATD allows the agency to automate and optimize the buying and placement of digital advertising, such as display and video ads, on various websites and platforms. This can help the agency to more effectively reach the client's target audience and achieve their desired marketing objectives. An ATD can also provide the agency with valuable data and insights into the performance of their advertising campaigns.