Some Practical Guidance for Rule 8.3 of the California Rules of Professional Conduct

February 6, 2026

By Anne M. Rudolph

Rule of Professional Conduct 8.3, titled “Reporting Professional Misconduct,” went into effect on August 1, 2023, making California the last state to implement a version of this rule. Referred to by many as the “rat rule” or “snitch rule,” rule 8.3 requires an attorney to report the ethical misconduct of other attorneys related to their honesty, trustworthiness and fitness as an attorney. The failure to report can result in discipline for an attorney who knew or should have known of the misconduct.

In its 2024 Annual Report,^{^[1]} the State Bar reported that in the first eight months after rule 8.3 went into effect, attorney-initiated complaints increased by 82% compared to the same period in the prior year. And, approximately 63% of the attorney-initiated complaints cited rule 8.3 as the basis for the filing. Complaints filed pursuant to rule 8.3 had the highest investigation rate by the Office of Chief Trial Counsel (69%) compared to nonattorney-initiated complaints (39%).

The 2025 Annual Report by the State Bar does not break down the same detailed statistics for rule 8.3 reporting.^[2]

Though it has now been in effect for over 2 years, rule 8.3 continues to generate controversy and confusion for California attorneys, many of whom struggle with determining what conduct is reportable. The purpose of this article is to provide a review of rule 8.3, and a list of additional sources that may assist with making a reporting determination.

Rule 8.3(a) provides that an attorney shall, without undue delay, when the attorney knows of credible evidence, report the following types of misconduct by other attorneys, when the misconduct raises a substantial question as to the attorney’s honesty, trustworthiness, or fitness as an attorney in other respects:

Criminal Acts
Conduct Involving:
- Dishonesty
- Fraud
- Deceit
- Misrepresentation (reckless or intentional)
- Misappropriation of Funds or Property

“Knows” means actual knowledge of the fact in question, which may be inferred from circumstances. (Rule 1.0.1(f).) “Substantial” when used in reference to degree or extent means “material matter of clear and weighty importance.” (Rule 1.0.1(l).)

Rule 8.3(b) provides that an attorney may, but is not required to, report any other violation of the Rules of Professional Conduct or the State Bar Act.

Rule 8.3(c) provides that for purposes of the rule, a “criminal act” excludes conduct that might be a crime in another jurisdiction but is not a crime in California.

Rule 8.3(d) provides that the duty to report does not apply under the following circumstances:

The information is privileged and/or confidential:
- Business & Professions Code section 6068, subdivision (e)
- Rule 1.6
- Rule 1.8.2
- Mediation confidentiality
- Attorney client privilege
The information is gained while participating in an ethics hotline or similar service
The information is learned while participating in a substance abuse or mental health program

To assist attorneys to be aware of their obligations, and to provide guidance on when reporting may or may not be required, the State Bar website contains a number of resources. Under the tab for “Ethics,” there is a section titled “Rule 8.3 Required Reporting.”^[3] In this section, there is an advisory video and a link to frequently asked questions. There is also a link to several hypothetical scenarios analyzing the rule 8.3 implications. You can also request a toolkit from the State Bar that provides its detailed analysis of rule 8.3, including several example fact patterns.

Further, because a version of rule 8.3 was adopted as part of the original Model Rules of Professional Conduct in 1983, and adopted by every other state before California, there are many ethics opinions and case law in other states that may provide some guidance in evaluating whether a particular situation requires reporting.

Lastly, an attorney struggling with a determination on whether certain conduct requires reporting under rule 8.3, should also consider consulting with an attorney who specializes in ethics to assist with the determination.

^[1] State Bar of California, 2024 Annual Report, Regulation and Discipline. https://annualreport.calbar.ca.gov/2023-digital-annual-report/regulation-and-discipline

^[2] State Bar of California, 2025 Annual Report, Regulation and Discipline. https://annualreport.calbar.ca.gov/2024-digital-annual-report/regulation-and-discipline

^[3] https://www.calbar.ca.gov/legal-professionals/legal-resource-center/ethics/rule-83-required-reporting

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