Section 4.3: Former, Prospective, and Imputed Conflicts

Key Takeaways

  • Rule 1.9 prohibits representing a client adverse to a former client in the same or a substantially related matter without written consent.
  • Matters are substantially related if they involve the same transaction or if there is a risk that confidential info would advance the new client's position.
  • Prospective client conflicts require that the information received be 'significantly harmful' to trigger disqualification.
  • Imputed disqualification treats a firm as a single unit, but does not apply to personal interest conflicts or sexual relations conflicts.
  • Imputation can be avoided when a lawyer changes firms if the conflicted lawyer is timely screened, receives no fee, and the former client receives notice.
Last updated: July 2026

Former, Prospective, and Imputed Conflicts (Rules 1.9, 1.10, 1.18)

Conflicts of interest do not disappear when a representation ends or if a formal representation never begins. Lawyers owe continuing duties of loyalty and confidentiality to former clients and prospective clients. Furthermore, under the principle of imputed disqualification, a conflict infecting one lawyer in a firm is generally attributed to all other lawyers in that firm. Understanding these transition rules and the screening mechanisms to overcome them is a frequent testing ground on the MPRE.

Duties to Former Clients (Rule 1.9)

Once a client-lawyer relationship concludes, the lawyer cannot represent a new client whose interests are adverse to the former client in the same or a substantially related matter.

The Substantially Related Test (Rule 1.9(a))

A lawyer who has formerly represented a client in a matter shall not thereafter represent 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.

Under Comment 3 to Rule 1.9, matters are "substantially related" if:

  • They involve the same transaction or legal dispute; or
  • There is a substantial risk that confidential factual information that would normally have been obtained in the prior representation would materially advance the new client's position in the subsequent matter.

For example, a lawyer who represented a developer in drafting a commercial lease cannot later represent a tenant seeking to void that lease. However, a lawyer who represented a client in a personal injury lawsuit ten years ago is not disqualified from representing a bank in suing that client for defaulting on a business loan today, because the two matters are completely unrelated and no relevant confidential information from the personal injury suit would advance the bank's position.

Use and Disclosure of Former Client Information (Rule 1.9(c))

A lawyer must not use information relating to a former representation to the disadvantage of the former client unless the information has become "generally known," or if the rules permit or require disclosure. "Generally known" is a high bar; it requires that the information be widely known within the relevant industry or community, not merely searchable in public archives or court records.

Duties to Prospective Clients (Rule 1.18)

A "prospective client" is a person who discusses with a lawyer the possibility of forming a client-lawyer relationship. Even if no representation ensues, the lawyer must protect the prospective client’s confidential information (Rule 1.18(b)).

The Disqualification Standard (Rule 1.18(c))

A lawyer shall not represent a client with interests materially adverse to those of a prospective client in the same or a substantially related matter if the lawyer received information from the prospective client that could be significantly harmful to the prospective client in that matter.

Key Distinction: While any material confidential information can disqualify a lawyer from opposing a former client under Rule 1.9, a prospective client's information must be "significantly harmful" to trigger disqualification. Significantly harmful information includes strategic plans, settlement caps, trade secrets, or explicit admissions of liability.

Overcoming Prospective Conflicts (Rule 1.18(d))

If a lawyer receives significantly harmful information, representation of an adverse party is permissible only if:

  1. Both the affected client and the prospective client give informed consent, confirmed in writing; OR
  2. The disqualified lawyer is screened. To qualify for the screening exception, the lawyer must have taken reasonable measures to avoid exposure to more disqualifying information than was reasonably necessary, must be timely screened, must receive no part of the fee, and written notice must be promptly given to the prospective client.

Imputed Disqualification (Rule 1.10)

The general rule of imputation treats a law firm as a single unit. Under Rule 1.10(a), if one lawyer in a firm is disqualified from representing a client due to a conflict of interest under Rule 1.7 or 1.9, the entire firm is disqualified.

Exceptions to Imputation

Imputation does not apply in two major circumstances:

  • Personal Interest Conflicts: If the conflict is based on a personal interest of the prohibited lawyer (such as their personal political beliefs, religious convictions, or a close family relationship) and does not present a significant risk of materially limiting the representation of the client by the remaining lawyers in the firm.
  • Sexual Relations: The prohibition on sexual relations with clients under Rule 1.8(j) is personal to the lawyer and is not imputed to the firm.

Screening to Avoid Imputation

When a lawyer moves from one private firm to another, the new firm can avoid imputed disqualification arising from the lawyer's former clients if the firm implements proper screening. Under Rule 1.10(a)(2), the firm is not disqualified if:

  1. Timely Screened: The personally disqualified lawyer is timely screened from any participation in the matter. The screen must be set up immediately upon the firm identifying the conflict.
  2. No Fee Apportionment: The disqualified lawyer is apportioned no part of the fee from the matter. (Note: A lawyer may still receive a regular salary or partner distribution that is not directly tied to the fees generated by the conflicted matter).
  3. Written Notice to Former Client: Written notice is promptly given to the former client to enable them to monitor compliance. This notice must include a description of the screening procedures, an agreement by the firm to respond to written inquiries, and a statement that review may be available before a tribunal.
  4. Compliance Certifications: The firm provides certifications of compliance to the former client upon request and at reasonable intervals.
Test Your Knowledge

A lawyer represented a local retail store in drafting its standard employment contract three years ago. The lawyer no longer represents the store. A former employee of the store now wants to hire the lawyer to sue the store for wrongful termination, alleging that the store's managers engaged in discriminatory firing practices. The store's standard employment contract is not in dispute. Does the lawyer have a conflict of interest that prevents them from representing the employee?

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Test Your Knowledge

A lawyer joins a new law firm. At their former firm, the lawyer represented a plaintiff in a patent infringement lawsuit against Company X. The lawyer's new law firm represents Company X in an unrelated intellectual property licensing negotiation. The new firm wants to continue representing Company X in the licensing matter. What must the new firm do to avoid imputed disqualification?

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Test Your Knowledge

A woman met with a lawyer for a 30-minute consultation to discuss a potential divorce from her husband. During the consultation, the woman disclosed detailed information about her husband's hidden bank accounts and her negotiation strategy. Ultimately, the woman decided not to hire the lawyer. Two months later, the husband approached the lawyer to represent him in the divorce proceeding. May the lawyer represent the husband?

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D