What does 'materially adverse' mean for conflicts with a former or prospective client, and does economic competition count?
ABA Formal Opinion 497: Conflicts Involving Materially Adverse Interests
Short answer: The opinion concludes that "materially adverse" in Model Rules 1.9(a) and 1.18(c) is broader than, but includes, direct adverseness: it clearly covers suing or negotiating against a former or prospective client, attacking the lawyer's own prior work, and in many instances cross-examining a former or prospective client on the same or a substantially related matter, while general economic or financial adverseness alone, without specific demonstrable harm, does not meet the threshold.
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 phrase "materially adverse," which appears in Model Rule 1.9(a) (duties to former clients) and Model Rule 1.18(c) (duties to prospective clients) but is defined in neither. It traces the term's history, noting that as adopted in 1983 a comment tied Rule 1.9 adverseness to Rule 1.7, and that the Ethics 2000 revisions deleted that sentence. The opinion concludes that material adverseness is not limited to "direct" adverseness, departing from the narrower reading of the earlier Formal Opinion 99-415.
The opinion holds that material adverseness clearly includes direct adverseness but can also exist without it, requiring a fact-specific look at whether the current representation causes legal, financial, or other identifiable detriment to the former client. It draws a line at economic competition: per the opinion, "general economic or financial adverseness alone does not constitute material adverseness," and material adverseness "requires a conflict as to the legal right and duties of the clients, not merely conflicting or competing economic interests."
The opinion identifies categories that count. Suing or defending against a former client is "a classic example of representing interests that are directly adverse and therefore 'materially adverse' to the interests of a former client," and negotiating across the table in a transactional matter typically qualifies. Attacking the lawyer's own prior work, such as challenging a patent the lawyer obtained or a covenant the lawyer drafted, creates a materially adverse conflict, even where the former client is not a party or witness. Cross-examining a former client may create a Rule 1.9(a) conflict where interests are materially adverse and the matters are substantially related, even if no confidential information will be used; the opinion notes Rule 1.9(c)(1) separately bars using a former client's information to its disadvantage unless generally known.
The opinion also sets a floor: there is a threshold below which adverseness is not material, and a claimed detriment unaccompanied by demonstrable or material harm does not suffice, or "materiality would have no meaning." It notes these conflicts may be addressed by informed consent confirmed in writing under Rule 1.9(a), by consent or screening under Rule 1.18(d), or, for the cross-examination problem, by having the current client retain separate, screened counsel for the examination.
In practice
Under this opinion, whether a conflict with a former or prospective client is "materially adverse" turns on a fact-specific analysis, not solely on whether the parties are directly opposite each other. The opinion holds that suing or negotiating against a former client, attacking the lawyer's own prior work, and cross-examining a former client on a substantially related matter generally qualify, while mere economic competition between clients, or a detriment without demonstrable material harm, does not. It identifies ways the conflict can be addressed: informed consent confirmed in writing under Rule 1.9(a) (which does not waive Rule 1.6 confidentiality duties), informed consent or screening under Rule 1.18(d) for prospective-client conflicts, and separate screened counsel to conduct a cross-examination of a former client.
Common questions
Q: Is "materially adverse" the same as being directly opposite a former client in litigation?
A: The opinion says direct adverseness is the classic example and always qualifies, but material adverseness is broader: it can exist even where the former client is not a party, if the current representation causes a specific, identifiable detriment.
Q: Does it count if I'm just competing economically with a former client?
A: Per the opinion, no. General economic or financial adverseness alone does not constitute material adverseness; the conflict must concern the legal rights and duties of the clients, not merely competing economic interests.
Q: Can I attack work I previously did for a former client?
A: The opinion says challenging the lawyer's own prior work for a former client on the same or a substantially related matter, such as a patent the lawyer obtained or a covenant the lawyer drafted, creates a materially adverse conflict.
Q: Can I cross-examine a former client?
A: The opinion says cross-examining a former client may create a Rule 1.9(a) conflict where interests are materially adverse and the matters are substantially related, even if no confidential information will be used. It notes the conflict can be addressed by having the current client retain separate, screened counsel for the examination.
Background and rules framework
The opinion interprets Model Rule 1.9 (duties to former clients), including the "materially adverse" language of 1.9(a), the substantial-relationship test in Comment [3], and the 1.9(c)(1) limit on using former-client information. It applies Model Rule 1.18 (duties to prospective clients), including the 1.18(c) bar and the 1.18(d) consent and screening exceptions, and references Model Rule 1.7 (current-client conflicts) for the "directly adverse" standard and Model Rule 1.6 (confidentiality).
Citations and references
Rules of Professional Conduct:
- ABA Model Rule 1.9 (former clients), including 1.9(a) and 1.9(c)(1)
- ABA Model Rule 1.18 (prospective clients), including 1.18(c) and 1.18(d)
- ABA Model Rule 1.7 (current-client conflicts; "directly adverse")
- ABA Model Rule 1.6 (confidentiality)
Other opinions cited:
- ABA Formal Op. 99-415 (1999): direct adverseness reading (departed from)
- ABA Formal Op. 92-367 (1992): examining a client; separate-counsel cure
- ABA Formal Op. 479 (2017): "generally known" information
- ABA Formal Op. 492 (2020): "significantly harmful" information
See also
- ABA Formal Op. 510: Avoiding Imputation of a Prospective-Client Conflict
- ABA Formal Op. 509: Confidential Government Information Disqualification
- ABA Formal Op. 499: Passive Investment in an ABS
Source
- Landing page: ABA Formal Ethics Opinions index
- Original PDF: aba-formal-opinion-497.pdf