A Smart Order Routing/Router (SOR) is a trade lifecycle component, often an automated liquidity seeking algorithm, that utilizes using a set real-time mechanisms to intelligently execute against specified liquidity. This may be across multiple venues, including exchanges, MTFs/ATS, Liquidity providers, Dark pools and internal pool of liquidity and also considering the behaviour and microstructure of the depth of book and destinations rules of execution to achieve a specified outcome. It uses a complex set of rules, usually known as Client Best Execution instructions, to determine the optimal destination and behaviour for an order taking into account parameters such as best price available, queue position, minimize trading costs and real-time market behaviours. The SOR must comply with the local Best Execution regulation, such as US RegNMS and European MiFID. It provides reporting and transparency in the way it has achieved the Best Execution goals. SOR requirement exists in all fragmented assets classes, such as Equities, FX and Fixed income, managing Order-driven as well as Quote-driven (ESP and RFQ) execution.