When can a lawyer use a former client's information because it is 'generally known'?
ABA Formal Opinion 479: The "Generally Known" Exception to Former-Client Confidentiality
Short answer: The opinion concludes that a lawyer may use a former client's information to the client's disadvantage without consent only when that information has become "generally known," meaning it is widely recognized by the public in the relevant geographic area or within the former client's industry, profession, or trade; information is not generally known merely because it is publicly available or contained in a public record.
Disclaimer: This is an advisory ethics opinion. Advisory opinions are not binding; they interpret the American Bar Association's Model Rules of Professional Conduct and are persuasive authority. This summary is for research purposes only and is not legal advice. Verify current rules before acting on any specific guidance.
About this page: The plain-English summary and Q&A below were written by Ezel based on the official opinion. We do not reproduce the opinion text on this page; follow the linked source for the official text, which controls.
Plain-English summary
The opinion interprets the "generally known" exception in Model Rule 1.9(c)(1), which lets a lawyer use a former client's information to that client's disadvantage once the information has become generally known. It first distinguishes the two parts of Rule 1.9(c): 1.9(c)(2) governs revealing or disclosing former-client information and carries the same duties as Rule 1.6, while 1.9(c)(1) governs use and contains the exception at issue. The opinion stresses that "the generally known exception applies only to the 'use' of former client confidential information," not to its disclosure.
Because "generally known" is not defined in the Rules, the opinion surveys courts, bar opinions, and the Restatement, and finds broad agreement that "information that is publicly available is not necessarily generally known." It adopts a two-part working definition: information is generally known if it is widely recognized by members of the public in the relevant geographic area, or widely recognized in the former client's industry, profession, or trade. The opinion notes that "information may be widely recognized within a former client's industry, profession, or trade without being widely recognized by the public," so the second route can apply even when the public at large is unaware of the information.
The opinion draws sharp limits. It states that information discussed in open court or available in court records, libraries, or other public repositories is not, standing alone, generally known. It adds that "certainly, if information is publicly available but requires specialized knowledge or expertise to locate, it is not generally known within the meaning of Model Rule 1.9(c)(1)," and that "for information to be generally known it must previously have been revealed by some source other than the lawyer or the lawyer's agents."
In practice
Under this opinion, a lawyer evaluating whether the Rule 1.9(c)(1) exception applies asks whether the information is widely recognized by the public in the relevant area or within the former client's field, as the opinion frames it under the Model Rule as it stood in 2017. The opinion holds that mere public availability, presence in a court record, or findability through specialized effort does not make information generally known, and that the exception authorizes use of the information rather than its disclosure, which remains governed by Rule 1.9(c)(2).
Common questions
Q: Does the "generally known" exception let me disclose a former client's information?
A: No. The opinion holds the exception applies only to the use of former-client information under Rule 1.9(c)(1); disclosure or revelation remains governed by Rule 1.9(c)(2) and Rule 1.6.
Q: Is information "generally known" just because it is in a public court record?
A: Per the opinion, no. Information discussed in open court or available in court records or other public repositories is not, standing alone, generally known.
Q: Can information be "generally known" if the general public has never heard of it?
A: Yes. The opinion concludes information widely recognized within the former client's industry, profession, or trade is generally known even if the public at large is unaware of it.
Q: What if the information is public but hard to find?
A: The opinion says that is not enough. Information that is publicly available but requires specialized knowledge or expertise to locate is not generally known.
Background and rules framework
The opinion interprets Model Rule 1.9 (duties to former clients), focusing on Rule 1.9(c)(1) (use of former-client information, with the "generally known" exception) and Rule 1.9(c)(2) (revealing former-client information). It reads these against Model Rule 1.6 (confidentiality of current-client information), to which Rule 1.9(c)(2) ties the disclosure duty.
Citations and references
Rules of Professional Conduct:
- ABA Model Rule 1.9 (former clients), including 1.9(c)(1) and 1.9(c)(2)
- ABA Model Rule 1.6 (confidentiality)
Other opinions cited:
- NYSBA Ethics Op. 991 (2013) and Op. 1125 (2017): information not generally known merely because in the public domain
- Illinois State Bar Ass'n Advisory Op. 05-01 (2006): "common knowledge in the community"
- Texas Ethics Op. 595 (2010): public-record information may not be generally known
- Restatement (Third) of the Law Governing Lawyers § 59 cmt. d (2000)
See also
- ABA Formal Op. 480: Confidentiality in Lawyer Blogging
- ABA Formal Op. 511R: Confidentiality When Posting to Listservs
- ABA Formal Op. 496: Responding to Online Criticism
Source
- Landing page: ABA Formal Ethics Opinions index
- Original PDF: aba-formal-opinion-479.pdf