Every organization wants to ensure that their information or money is not misused by employees or external contractors. As part of the effort to ensure that individuals will not act maliciously, companies perform background checks or background screenings on potential or current employees and expect contractors and other third parties to do the same.
Past criminal behavior or other misconduct is believed to be a good indication of the potential for further criminal behavior or misconduct. Companies want to seek an explanation for any past inappropriate or illegal behaviors and either seek explanations or pass on the candidate, if appropriate.
Organizations expect that companies they use the services for, or share sensitive information with, have a strong policy in place requiring pre-employment background checks and, depending on the nature of the relationship and information involved, perform periodic background checks on employees with privileged access.