IT outsourcing is the practice of subcontracting responsibility for all or part of an IT function to a third-party service provider that manages the work. Businesses use IT outsourcing for functions ranging from infrastructure to software development, maintenance and support.
IT outsourcing has existed since the earliest days of business computing, beginning in the late 1950s with the service bureau operations of major hardware vendors such as IBM, Burroughs, Univac and Control Data. Outsourcing IT is viewed as a way to reduce costs, improve operational flexibility, increase service levels, reduce management overhead or rapidly deploy new capabilities. Most large organizations only outsource a portion of any given IT function.