An Authority to Operate (ATO) is a formal authorization granted by an agency's authorizing official that permits an information system to operate at an acceptable level of risk. Required under the Federal Information Security Modernization Act (FISMA) and governed by the NIST Risk Management Framework (RMF), an ATO represents the culmination of security categorization, control selection, implementation, assessment, and risk acceptance.
The ATO process typically takes 6-18 months and produces a body of documentation including the System Security Plan (SSP), Security Assessment Report (SAR), and Plan of Action and Milestones (POA&M). Continuous monitoring is required throughout the authorization period, and the ATO must be renewed periodically — typically every three years, though some agencies have moved toward continuous ATO models that authorize on an ongoing basis.
For contractors, demonstrating ATO readiness or holding an existing ATO for similar systems is a significant competitive advantage in IT service procurements. A contractor that can inherit controls from an existing ATO boundary reduces the time to operational capability dramatically. Conversely, a contractor without ATO experience faces a steep learning curve on contracts that require an authorized system.