Complete Discovery Source or CDS is an e-discovery services and software company based in New York City, New York, United States. It provides litigation support services for the electronic discovery phases of litigation and investigations. The company supports both industry and proprietary tools to handle electronic evidence. It is one of the largest service providers offering the review tool, Relativity, which is a document review and processing tool used by law firms and in-house counsel within corporations. It is headquartered in New York and has regional offices located in Chicago and Washington, DC. CDS maintains national data centers in New York, New Jersey, and Washington, DC as well as a European Union data center in London, UK. These facilities host large volumes of e-discovery for processing, review, and storage. Since 2013, CDS has been named "Best" e-discovery provider in the annual national survey by the New York Law Journal three times. In 2013, 2014, 2015, and 2016 the National Law Journal also ranked CDS as the "Best End-to-End e-Discovery Solution" and "Best Managed eDiscovery and Litigation Support" in their national rankings.