Also known as: ABA Rule 1.9 · Model Rule 1.9
Written by attorneys · grounded in primary & secondary sources — see below
A rule of professional conduct that prohibits a lawyer who has formerly represented a client in a matter from thereafter representing another person in the same or a substantially related matter in which that person's interests are materially adverse to the interests of the former client unless the former client gives informed consent confirmed in writing.
Select any source to read its text and confirm it supports the definition.
Lina consulted Patel about suing her former employer but chose not to retain him after describing the employer's confidential repository structure and launch timelines. Months later HexaCloud asked Patel to represent it in a licensing deal involving similar products. Patel may not use or reveal Lina's disclosures because Rule 1.9 would bar such use if Lina had been a former client.
Maya previously defended Redstone Produce in a contamination case while at another firm. After joining BrightFork she recalls Redstone's internal quality control procedures. BrightFork now seeks to sue Redstone on behalf of Harbor Grill in a related food safety class action. The firm may proceed only if it timely screens Maya, denies her any fee from the matter, and provides Redstone prompt written notice of the safeguards.
Matters are substantially related when they involve the same transaction or legal dispute or when there is a substantial risk that confidential information acquired during the prior representation would be relevant to the new matter. Overlap in factual or legal issues that would normally have revealed protected information satisfies the test even if the new claims address later events.
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No. The prohibition applies whenever the lawyer personally acquired material protected information from the former firm's representation of the client. Access to confidential documents or participation in strategy sessions triggers the restriction even if the lawyer did not lead the matter.
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A lawyer may use or reveal information from a prospective client only in the limited circumstances in which the lawyer could use or reveal information of a former client under Rule 1.9. Absent informed consent or another exception such as the information becoming generally known, the lawyer may not use the information to the prospective client's disadvantage.
Supporting sources
When a lawyer's conflict arises from a prior firm's representation, the new firm avoids disqualification by timely screening the lawyer from the matter, apportioning no fee to the lawyer, and promptly giving the affected former client written notice describing the procedures. These steps permit the firm to proceed despite the personal disqualification.
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