The law starts with the examiner
California has brought professionals who examine AI models under regulation. Assembly Bill 1405, signed by governor Gavin Newsom on 9 September 2026, requires a public auditor registry by 1 January 2029 and sets conditions for selling certain audits. From that date, a person may not offer, sell or conduct a “covered AI audit” without being registered.
The word “covered” limits the law’s reach. AB 1405 defines such an audit as an assessment of internal controls, processes or systems implemented to ensure that an AI system or model complies with state law. That definition separates covered audits from technical comments, academic evaluations or informal tests that do not assess controls, processes or systems necessary for legal compliance. The prohibition applies to anyone offering, selling or conducting the covered work, even if not all three activities are involved.
On the same day, 9 September, California enacted SB 813, which creates a framework for designating independent verification organisations. The statute centres their role on assessing the risks posed by AI systems and models and developing metrics and methodologies. It also clarifies that an organisation need not audit legal compliance in order to register with the agency. The governor’s announcement described the law as a route to assess compliance with state rules; that summary does not replace the more precise definition in the enacted text. AB 1405 addresses another part of the system: who may offer a covered audit, what they must disclose and which independence rules they must follow.
A registration number is not a medal
California’s Government Operations Agency must create the registry and issue each auditor a unique number. That number must appear prominently in advertising materials that offer or solicit covered audit services. The agency will publish information supplied by auditors and establish a mechanism for people to report misconduct by registered professionals.
The law also bars the registry from being sold as an endorsement. The state website must prominently say that registration is not a recommendation or endorsement by California. The distinction sounds obvious until it meets an advertisement: “state-registered” can sound like a state evaluation, even though registration does not declare that a system has passed a safety test. The legislature anticipated the confusion and required the registry interface to address it.
Registration does require information that enables scrutiny of the auditor. Applicants must identify the California laws or regulations their services assess, relevant certifications and the standards they use. The law requires operating procedures and a description of the basis for claims about the accuracy, reliability or validity of their protocols. Reasonable redactions are allowed to protect trade secrets. The agency publishes information it receives, but each audit report does not become a public document merely because a registry exists.
That point determines whom the assessment addresses. AB 1405 requires the auditor to provide its report to the auditee. The report must describe its objectives and scope, present results and supporting evidence, identify deficiencies and, where appropriate, recommend reasonable corrective measures. It must also say whether the auditee implemented and followed the internal safety standards and protocols within the scope. The report must state what fell outside the assessment and which material gaps in evidence, information, systems or access limited the work. The auditor signs and dates a statement that the audit complied with the law. The immediate recipient is the organisation being assessed; this registry rule does not require the full report to be published.
Independence means more than not working for the company
The auditor will be paid by the client. AB 1405 does not treat reasonable compensation, by itself, as destroying independence. It bars an audit where a financial, employment, business or other relationship could reasonably impair objectivity. It also prevents an auditor from evaluating its own work—for example, controls it designed or implemented for the client—and bars a person on the audit from negotiating for or accepting a job with that client while participating. Someone who had material responsibility for, or material participation in, the subject matter during the preceding 12 months may not be assigned to review it.
The law recognises the conflict without relying on a convenient fiction: being paid by the client does not automatically make an outside auditor dependent, but the word “external” does not prove impartiality either. Registration can establish formal requirements; it cannot replace judgement about each engagement. The report must show its basis and limits precisely because institutional independence and audit quality are tested in particular jobs.
Record retention matters too. Auditors must keep, for at least ten years, documents supplied to the client and information necessary to support their findings. That duty makes it possible to reconstruct what was examined if a dispute later arises, though records alone do not guarantee that the audit was deep or that the auditor had sufficient access. The requirement to disclose access gaps leaves that possibility visible.
The state may investigate complaints, remove an auditor from the registry and refer a violation to the attorney general or another enforcement authority. AB 1405 also protects specified whistleblowing from retaliation by auditors themselves. The registry regulates the conduct of registered providers; any liability for a system’s harms will depend on other laws and the facts of the case.
California regulates audit work, not the model’s outcome
An audit answers bounded questions: which controls exist, how they operate, what evidence supports them and which deficiencies remain. It cannot by itself determine whether a model is fair in every context, safe for every future use or ready for deployment. A result that tests compliance with one specific obligation may not cover the system’s effects on other groups, other languages, a later model version or uses the client left outside the engagement.
AB 1405 makes some of those boundaries mandatory report content. Auditors must detail objectives, results, supporting evidence, deficiencies and limits, so a bounded assessment is described as such rather than as general certification. A company receiving the report cannot faithfully present a narrow assessment as though it covered every conceivable risk; the auditor must record what it did not examine.
The mechanism still has an uncomfortable dependency: the company hires the reviewer and receives the report. The law introduces independence criteria, transparency, record retention, complaint channels and state oversight to discipline that relationship. It does not erase the client’s incentive to choose an audit that suits its business or guarantee unrestricted access to all data. Its contribution is to make it harder to hide those conditions behind a solemn word.
The registry number confirms that an auditor is registered. To judge the work, readers will need to know what was examined, under which standard, with what access and which limits the report records. California chose to regulate those selling that answer and barred the state from appearing to guarantee each judgement. The audit’s quality remains visible in the report, especially in what it admits it could not know.