Data theft is a growing phenomenon primarily caused by system administrators and office workers with access to technology such as database servers, desktop computers and a growing list of hand-held devices capable of storing digital information, such as USB flash drives, iPods and even digital cameras. Since employees often spend a considerable amount of time developing contacts, confidential, and copyrighted information for the company they work for, they may feel they have some right to the information and are inclined to copy and/or delete part of it when they leave the company, or misuse it while they are still in employment. Information can be sold and bought and then used by criminals and criminal organizations. Alternatively, an employee may choose to deliberately abuse trusted access to information for the purpose of exposing misconduct by the employer. From the perspective of the society, such an act of whistleblowing can be seen as positive and is protected by law in certain situations in some jurisdictions, such as the USA.

A common scenario is where a sales person makes a copy of the contact database for use in their next job. Typically, this is a clear violation of their terms of employment.

Notable acts of data theft include those by leaker Chelsea Manning and self-proclaimed whistleblowers Edward Snowden and Hervé Falciani.