Accountability is a foundational legal principle of the EU AI Act that assigns clear, specific responsibilities and liability for the compliance and safe operation of an AI system to defined economic operators in the supply chain, primarily the Provider and the Deployer.

This principle ensures there is always an identifiable legal entity that can be held responsible if an AI system causes harm or violates the law. Accountability transforms ethical aspirations into enforceable legal obligations. Under the Act, accountability is not vague or collective; it is precisely distributed based on an operator's role in bringing the system to market or putting it into use. The Provider is accountable for designing a compliant system, while the Deployer is accountable for using it properly. This creates a chain of responsibility where each party must demonstrate due diligence, through documentation, quality management, and risk mitigation, and can be subject to audits, penalties, and liability claims for failures.

The EU AI Act delineates accountability across key roles in the AI value chain:

Provider: Bears primary responsibility for ensuring the high-risk AI system complies with all mandatory requirements (e.g., risk management, data governance, technical documentation) before placing it on the market. They are liable for conformity assessment and CE marking.

Deployer: The entity using the AI system under its authority is accountable for proper use in accordance with instructions, implementing human oversight, monitoring operation, and reporting serious incidents.

Importer/Distributor: Have obligations to verify the Provider's conformity, ensure proper documentation is present, and must not supply systems they know or suspect to be non-compliant.

Authorized Representative: A designated natural or legal person within the EU who acts on behalf of a non-EU Provider, sharing accountability for making technical documentation available to authorities.

Regulatory Context: The entire structure of the EU AI Act is built on an accountability framework. Title III, "Obligations of Providers and Deployers," explicitly allocates duties. Market surveillance authorities (Title IX) are empowered to enforce these obligations, with the ability to impose significant administrative fines (Article 99) scaled to the severity of the infringement and the operator's role.

Enforcement and Deterrence: The explicit allocation of accountability serves as a powerful deterrent against negligent development or deployment. It provides a clear path for redress for individuals harmed by AI systems and gives regulatory bodies a direct target for enforcement actions. For organizations, it necessitates clear internal governance to manage and document the fulfillment of their assigned obligations.