Also known as: substantially related matters · substantial relationship · substantial relationship test
Written by attorneys · grounded in primary & secondary sources — see below
2 senses
A matter sharing substantial factual or legal overlap with a prior or prospective client representation such that confidential information from the earlier matter would likely prove material to the later one. Overlap exists when the two matters involve the same transaction, the same parties, or closely related legal issues that would make it reasonable to conclude the lawyer gained relevant confidences. The test protects client confidences while permitting representation when no realistic risk of misuse exists.
A relationship between a nonparent and a child that meets statutory criteria for standing to seek custody or visitation. The relationship must be substantial and its denial must risk harm to the child. Courts examine the duration, nature, and quality of the nonparent's involvement with the child.
Each sense below has its own examples, sources, and questions.
A matter sharing substantial factual or legal overlap with a prior or prospective client representation such that confidential information from the earlier matter would likely prove material to the later one. Overlap exists when the two matters involve the same transaction, the same parties, or closely related legal issues that would make it reasonable to conclude the lawyer gained relevant confidences. The test protects client confidences while permitting representation when no realistic risk of misuse exists.
Select any source to read its text and confirm it supports the definition.
Sydney Santos consults a lawyer about a potential breach claim against a vendor but never retains the firm. Months later the firm is asked to represent another client suing the same vendor over nearly identical contract language. The firm must decline because the matters are substantially related and the lawyer received information from Sydney that could be significantly harmful.
Seth Shapiro represented Stonehaven Properties in a complex financing while at his old firm. After joining a new firm, the new firm is asked to sue Stonehaven over the same financing documents. Stonehaven moves to disqualify, triggering a rebuttable presumption that Seth received confidential information that the new firm must screen to avoid disqualification.
Sarah Sullivan drafted a supply agreement for Silverline Industries. Two years later another client asks her to sue Silverline for breach of a nearly identical agreement. Without informed consent confirmed in writing, Sarah may not accept the new matter because it is substantially related and materially adverse to her former client.
Rule 1.9 bars representation adverse to a former client in the same or a substantially related matter without informed consent. Rule 1.18 adds the requirement that the lawyer received information from the prospective client that could be significantly harmful before disqualification attaches.
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The new firm must rebut the presumption that the migrating lawyer received confidential information by demonstrating effective, timely screening that prevents any involvement in the matter and any sharing in fees derived from it.
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A relationship between a nonparent and a child that meets statutory criteria for standing to seek custody or visitation. The relationship must be substantial and its denial must risk harm to the child. Courts examine the duration, nature, and quality of the nonparent's involvement with the child.
Select any source to read its text and confirm it supports the definition.
Selena Singh cared for her niece daily for four years while the child's parents worked long hours. After the parents separated and cut off contact, Selena petitions for visitation. The court must decide whether her consistent caregiving created a substantial relationship whose denial would harm the child.
Compensation alone does not disqualify the relationship. The statute focuses on whether the nonparent functioned as a consistent caretaker without expectation of compensation from the parents, but paid caregiving through an employer program may still support standing if the other statutory elements are met.
Supporting sources
Scott Summers worked at a firm that represented Sapphire Holdings in a licensing dispute. After Scott left, the firm is asked to represent a competitor suing Sapphire over the same license. The firm may not proceed if any remaining lawyer possesses material confidential information from the prior matter unless Sapphire gives informed consent in writing.
Overlap in contract language creates a substantially related matter when the current dispute centers on provisions the lawyer previously drafted or negotiated, because confidential insights about drafting intent or risk allocation would likely be material.
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