(1) whose interests are materially adverse to that person; and

(2) about whom the attorney had acquired information protected by Rules 19-301.6 (1.6) and 19-301.9 (c) (1.9) that is material to the matter; unless the former client gives informed consent, confirmed in writing.

(1) use information relating to the representation to the disadvantage of the former client except as these Rules would permit or require with respect to a client, or when the information has become generally known; or

(2) reveal information relating to the representation except as these Rules would permit or require with respect to a client.

[1] After termination of a client-attorney relationship, an attorney has certain continuing duties with respect to confidentiality and conflicts of interest and thus may not represent another client except in conformity with this Rule. Under this Rule, for example, an attorney could not properly seek to rescind on behalf of a new client a contract drafted on behalf of the former client. So also an attorney who has prosecuted an accused person could not properly represent the accused in a subsequent civil action against the government concerning the same transaction. Nor could an attorney who has represented multiple clients in a matter represent one of the clients against the others in the same or a substantially related matter after a dispute arose among the clients in that matter, unless all affected clients give informed consent. See Comment [9]. Current and former government attorneys must comply with this Rule to the extent required by Rule 19-301.11 (1.11).

[2] The scope of a “matter” for purposes of this Rule depends on the facts of a particular situation or transaction. The attorney's involvement in a matter can also be a question of degree. When an attorney has been directly involved in a specific transaction, subsequent representation of other clients with materially adverse interests in that transaction clearly is prohibited. On the other hand, an attorney who recurrently handled a type of problem for a former client is not precluded for that reason alone from later representing another client in a factually distinct problem of that type even though the subsequent representation involves a position adverse to the prior client. Similar considerations can apply to the reassignment of military attorneys between defense and prosecution functions within the same military jurisdictions. The underlying question is whether the attorney was so involved in the matter that the subsequent representation can be justly regarded as a changing of sides in the matter in question.

[3] Matters are “substantially related” for purposes of this Rule if they involve the same transaction or legal dispute or if there otherwise is a substantial risk that confidential factual information as would normally have been obtained in the prior representation would materially advance the client's position in the subsequent matter. For example, an attorney who has represented a businessperson and learned extensive private financial information about that individual may not then represent that individual's spouse in seeking a divorce. Similarly, an attorney who has previously represented a client in securing environmental permits to build a shopping center would be precluded from representing neighbors seeking to oppose rezoning of the property on the basis of environmental considerations; however, the attorney would not be precluded, on the grounds of substantial relationship, from defending a tenant of the completed shopping center in resisting eviction for nonpayment of rent. Information that has been disclosed to the public or to other parties adverse to the former client ordinarily will not be disqualifying. Information acquired in a prior representation may have been rendered obsolete by the passage of time, a circumstance that may be relevant in determining whether two representations are substantially related. In the case of an organizational client, general knowledge of the client's policies and practices ordinarily will not preclude a subsequent representation; on the other hand, knowledge of specific facts gained in a prior representation that are relevant to the matter in question ordinarily will preclude such a representation. A former client is not required to reveal the confidential information learned by the attorney in order to establish a substantial risk that the attorney has confidential information to use in the subsequent matter. A conclusion about the possession of such information may be based on the nature of the services the attorney provided the former client and information that would in ordinary practice be learned by an attorney providing such services.

Attorneys Moving Between Firms--[4] When attorneys have been associated within a firm but then end their association, the question of whether an attorney should undertake representation is more complicated. There are several competing considerations. First, the client previously represented by the former firm must be reasonably assured that the principle of loyalty to the client is not compromised. Second, the rule should not be so broadly cast as to preclude other persons from having reasonable choice of attorneys. Third, the rule should not unreasonably hamper attorneys from forming new associations and taking on new clients after having left a previous association. In this connection, it should be recognized that today many attorneys practice in firms, that many attorneys to some degree limit their practice to one field or another, and that many move from one association to another several times in their careers. If the concept of imputation were applied with unqualified rigor, the result would be radical curtailment of the opportunity of attorneys to move from one practice setting to another and of the opportunity of clients to change attorneys.

[5] Section (b) of this Rule operates to disqualify the attorney only when the attorney involved has actual knowledge of information protected by Rules 19-301.6 (1.6) and 19-301.9 (c) (1.9). Thus, if an attorney while with one firm acquired no knowledge or information relating to a particular client of the firm, and that attorney later joined another firm, neither the attorney individually nor the second firm is disqualified from representing another client in the same or a related matter even though the interests of the two clients conflict. See Rule 19-301.10 (b) (1.10) for the restrictions on a firm once an attorney has terminated association with the firm.

[6] Application of section (b) of this Rule depends on a situation's particular facts, aided by inferences, deductions or working presumptions that reasonably may be made about the way in which attorneys work together. An attorney may have general access to files of all clients of a law firm and may regularly participate in discussions of their affairs; it should be inferred that such an attorney in fact is privy to all information about all the firm's clients. In contrast, another attorney may have access to the files of only a limited number of clients and participate in discussions of the affairs of no other clients; in the absence of information to the contrary, it should be inferred that such an attorney in fact is privy to information about the clients actually served but not those of other clients. In such an inquiry, the burden of proof ordinarily rests upon the firm whose disqualification is sought.

[7] Independent of the question of disqualification of a firm, an attorney changing professional association has a continuing duty to preserve confidentiality of information about a client formerly represented. See Rules 19-301.6 (1.6) and 19-301.9 (c) (1.9).

[8] Section (c) of this Rule provides that information acquired by the attorney in the course of representing a client may not subsequently be used or revealed by the attorney to the disadvantage of the client. However, the fact that an attorney has once served a client does not preclude the attorney from using generally known information about that client when later representing another client.

[9] The provisions of this Rule are for the protection of former clients and can be waived if the client gives informed consent, which consent must be confirmed in writing under sections (a) and (b) of this Rule. See Rule 19-301.0 (g) (1.0). With regard to the effectiveness of an advance waiver, see Comment [22] to Rule 19-301.7 (1.7). With regard to disqualification of a firm with which an attorney is or was formerly associated, see Rule 19-301.10 (1.10).

Model Rules Comparison: Rule 19-301.9 (1.9) is substantially similar to the language of the Ethics 2000 Amendments to the ABA Model Rules of Professional Conduct except for wording changes to Comments [2] and [6].