Best execution refers to the duty of an investment services firm (such as a stock broker) executing orders on behalf of customers to ensure the best execution possible for their customers' orders. Some of the factors the broker must consider when seeking best execution of their customers' orders include: the opportunity to get a better price than what Is currently quoted, and the likelihood and speed of execution. For most broker-dealers or execution agents, best executions are usually optimally constructed via either static or dynamic programming.