# Del. Lawyers' R. Prof'l Conduct 1.9: Rule 1.9. Duties to former clients

> Delaware · Court rules · In force

URL: https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_9

## Section

- **Citation:** Del. Lawyers' R. Prof'l Conduct 1.9
- **Heading:** Rule 1.9. Duties to former clients
- **Jurisdiction:** Delaware
- **Kind:** Court rules
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Delaware Court Rules / Delaware Lawyers' Rules of Professional Conduct / Delaware Lawyers' Rules of Professional Conduct with comments / Del. Lawyers' R. Prof'l Conduct 1.9

## Text

« 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.
(b) A lawyer shall not knowingly represent a person in the same or a
substantially related matter in which a firm with which the lawyer
formerly was associated had previously represented a client:
(1) whose interests are materially adverse to that person; and
(2) about whom the lawyer had acquired information protected by Rules
1.6 and 1.9(c) that is material to the matter;
unless the former client gives informed consent, confirmed in writing.
(c) A lawyer who has formerly represented a client in a matter or whose
present or former firm has formerly represented a client in a matter shall
not thereafter:
(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.

COMMENT

[1] After termination of a client-lawyer relationship, a lawyer 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, a lawyer could not properly seek to
rescind on behalf of a new client a contract drafted on behalf of the former
client. So also a lawyer who has prosecuted an accused person
relationship, a lawyer 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, a lawyer could not properly seek to
rescind on behalf of a new client a contract drafted on behalf of the former
client. So also a lawyer 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 a lawyer 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
lawyers must comply with this Rule to the extent required by Rule 1.11.
[2] The scope of a “matter” for purposes of this Rule depends on the
facts of a particular situation or transaction. The lawyer’s involvement in a
matter can also be a question of degree. When a lawyer 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, a lawyer who recurrently handled a type of
problem for a former client is not precluded 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 there assignment of military lawyers
between defense and prosecution functions within the same military
jurisdictions. The underlying question is whether the lawyer was so
involved in the matter that the subsequent representation can be justly
regarded as a changing of sides in the matter in question
entation involves a position adverse to the prior client.
Similar considerations can apply to there assignment of military lawyers
between defense and prosecution functions within the same military
jurisdictions. The underlying question is whether the lawyer 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, a lawyer who
has represented a business person and learned extensive private financial
information about that person may not then represent that person’s spouse
in seeking a divorce. Similarly, a lawyer 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
lawyer 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
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
lawyer 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 lawyer in order to
establish a substantial risk that the lawyer 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 lawyer provided
the former client and information that would in ordinary practice be learned
by a lawyer providing such services.
[4] Lawyers Moving Between Firms. — When lawyers have been
associated within a firm but then end their association, the question of
whether a lawyer 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 legal counsel
ion of
whether a lawyer 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 legal counsel. Third, the rule should not unreasonably
hamper lawyers 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 lawyers practice in firms, that many lawyers
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 lawyers to move from one
practice setting to another and of the opportunity of clients to change
counsel.
[5] Paragraph (b) operates to disqualify the lawyer only when the lawyer
involved has actual knowledge of information protected by Rules 1.6 and
1.9(c). Thus, if a lawyer while with one firm acquired no knowledge or
information relating to a particular client of the firm, and that lawyer later

joined another firm, neither the lawyer 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
1.10(b) for the restrictions on a firm once a lawyer has terminated
association with the firm.
[6] Application of paragraph (b) depends on a situation’s particular
facts, aided by inferences, deductions or working presumptions that
reasonably may be made about the way in which lawyers work together
n the same or a related
matter even though the interests of the two clients conflict. See Rule
1.10(b) for the restrictions on a firm once a lawyer has terminated
association with the firm.
[6] Application of paragraph (b) depends on a situation’s particular
facts, aided by inferences, deductions or working presumptions that
reasonably may be made about the way in which lawyers work together. A
lawyer 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 a lawyer in fact is privy to all information about all the
firm’s clients. In contrast, another lawyer 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 a lawyer 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 should rest upon the firm whose disqualification is
sought.
[7] Independent of the question of disqualification of a firm, a lawyer
changing professional association has a continuing duty to preserve
confidentiality of information about a client formerly represented. See
Rules 1.6 and 1.9(c).
[8] Paragraph (c) provides that information acquired by the lawyer in
the course of representing a client may not subsequently be used or revealed
by the lawyer to the disadvantage of the client. However, the fact that a
lawyer has once served a client does not preclude the lawyer 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 paragraphs (a) and (b). See Rule
1.0(e). With regard to the effectiveness of an advance waiver, see
Comment [22] to Rule 1.7
sing
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 paragraphs (a) and (b). See Rule
1.0(e). With regard to the effectiveness of an advance waiver, see
Comment [22] to Rule 1.7. With regard to disqualification of a firm with
which a lawyer is or was formerly associated, see Rule 1.10.

NOTES TO DECISIONS

Client relations.
— Conflicts of interest.
— Disqualification.
— “Former client status”.
Analysis
— Shareholders’ derivative suits.
Professional conduct.
— Candor to the tribunal.
Client relations.
— Conflicts of interest.
Because the defendant did not object to a law firm’s representation of
the plaintiff during the negotiations of a merger agreement, and failed to
point to information or confidences obtained by the firm in its prior work
for the defendant that would have a material influence on the proceedings,
there was no basis to disqualify the firm. Rohm & Haas Co. v. Dow Chem.
Co., 2009 Del. Ch. LEXIS 249 (Del. Ch. Feb. 12, 2009).
Public defender’s office failed to prove an actual conflict of interest
existed in the office’s prior representation of a State’s witness and
defendant, and was not entitled to withdraw as counsel for defendant,
because: (1) the office’s representation of the witness and defendant were
not substantially related; and (2) the witness was represented by a
different public defender than those representing defendant. State v. Kent,
2014 Del. Super. LEXIS 558 (Del. Super. Ct. Sept. 3, 2014)
s prior representation of a State’s witness and
defendant, and was not entitled to withdraw as counsel for defendant,
because: (1) the office’s representation of the witness and defendant were
not substantially related; and (2) the witness was represented by a
different public defender than those representing defendant. State v. Kent,
2014 Del. Super. LEXIS 558 (Del. Super. Ct. Sept. 3, 2014).
Law firm who had helped a corporate debtor sell a portfolio of leases,
and who was later hired by real estate professionals, was not disqualified
from representing the professionals in an adversary proceeding filed by
California limited liability companies (LLCs) alleging that the
professionals committed fraud to obtain a higher price for the portfolio
merely because the firm had represented the LLCs in other cases; the
LLCs failed to show that there was a substantial relationship between

cases where the law firm served as the LLCs’ counsel and the adversary
proceeding the LLCs filed against the debtors’ professionals, or that the
law firm obtained information about the LLCs while representing them in
other cases that it could not use without violating Law. Prof. Conduct R.
1.9. Alamo Group, LLC v. A&G Realty Partners, LLC, 2015 Bankr. LEXIS
467 (Bankr. D. Del. Feb. 2, 2015), dismissed without prejudice, 529 B.R.
825 (Bankr. D. Del. 2015).
Trust beneficiaries’ defense of counsel’s conflict of interest was waived
because the beneficiaries failed to raise this issue as a defense to the
trustees’ application for attorneys’ fees in a timely manner, despite
multiple opportunities to do so. In re Hawk Mt. Trust, 2015 Del. Ch.
LEXIS 236 (Del. Ch. Sept. 8, 2015).
— Disqualification.
An attorney’s representation of a client who was suing a former client
on a matter substantially related to one on which the attorney previously
worked was an ethical violation resulting in the attorney’s disqualification.
Webb v. E.I. Du Pont De Nemours & Co., 811 F. Supp. 158 (D. Del. 1992)
o do so. In re Hawk Mt. Trust, 2015 Del. Ch.
LEXIS 236 (Del. Ch. Sept. 8, 2015).
— Disqualification.
An attorney’s representation of a client who was suing a former client
on a matter substantially related to one on which the attorney previously
worked was an ethical violation resulting in the attorney’s disqualification.
Webb v. E.I. Du Pont De Nemours & Co., 811 F. Supp. 158 (D. Del. 1992).
Defendant’s motion to disqualify plaintiff’s counsel under the former
version of this rule was denied, as defendant had no reasonable basis to
conclude that an attorney-client relationship had been established with
plaintiff’s counsel at an earlier meeting, and defendant failed to show
prejudice from disclosure of information exchanged at the meeting
because defendant later disclosed much of this information in a proxy
statement and in discussions with plaintiff. Benchmark Capital Ptnrs. IV,
L.P. v. Vague, 2002 Del. Ch. LEXIS 108 (Del. Ch. Sept. 3, 2002).
Trial court denied a motion to disqualify plaintiff’s counsel, as prior
representation of a defendant by the same law firm involved a case that
was not at all substantially related; any alleged release of confidential
information was deemed minimal by the trial court. Sanchez-Caza v. Estate
of Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept. 16, 2004).
Violation of Law. Prof. Conduct R. 1.9 does not require automatic
disqualification; a court reviewing the motion must weigh the effect of
any alleged conflict upon the fairness and integrity of the proceedings
any alleged release of confidential
information was deemed minimal by the trial court. Sanchez-Caza v. Estate
of Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept. 16, 2004).
Violation of Law. Prof. Conduct R. 1.9 does not require automatic
disqualification; a court reviewing the motion must weigh the effect of
any alleged conflict upon the fairness and integrity of the proceedings

before disqualifying the challenged counsel. Sanchez-Caza v. Estate of
Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept. 16, 2004).
Party seeking to disqualify opposing council based on council’s prior
representation of it is not required to point to specific confidential
information that it believes the council possesses. Acierno v. Hayward,
2004 Del. Ch. LEXIS 138 (Del. Ch. July 1, 2004).
State Department of Transportation (DOT) presented evidence that
arguably supported disqualification of plaintiff’s lawyer based on a
conflict of interest (in that the attoney inevitably would be placed in a
position
where
confidential
information
obtained
from
prior
representation of DOT would be used to its disadvantage in the litigation)
under Law Prof. Conduct R. 1.9.; the threat to the fair and efficient
administration of justice was sufficiently palpable to support the court’s
exercise of jurisdiction over DOT’s motion to disqualify. Acierno v.
Hayward, 2004 Del. Ch. LEXIS 138 (Del. Ch. July 1, 2004).
In a suit for a declaratory judgment as to a lessee’s obligations under a
lease, counsel for the lessor was not subject to disqualification under
Model Rules Prof’l Conduct R. 1.9 because: (1) counsel’s prior
representation of the lessee was limited to regulatory findings and
terminated upon the closing of a transfer of stock; (2) the nature of the
current litigation was a landlord-tenant dispute that was unrelated to the
prior representation; and (3) the information provided to counsel in the
prior representation was not likely to be relevant to the current litigation
because: (1) counsel’s prior
representation of the lessee was limited to regulatory findings and
terminated upon the closing of a transfer of stock; (2) the nature of the
current litigation was a landlord-tenant dispute that was unrelated to the
prior representation; and (3) the information provided to counsel in the
prior representation was not likely to be relevant to the current litigation.
Integrated Health Servs. v. THCI, Co. LLC, 327 B.R. 200 (D. Del. 2005).
In a real estate dispute, the mere fact that counsel for one party had once
advised a long-dead partner of an opposing party in entirely unrelated
matters was not grounds for disqualification of counsel; there was simply
no basis for supposing any impropriety or unfairness. Hendry v. Hendry,
2005 Del. Ch. LEXIS 187 (Del. Ch. Dec. 1, 2005).
Where attorney disqualification was sought under Model Rules of Prof’l
Conduct R. 1.9, which Delaware had adopted, plaintiff’s argument that
no conflict arose from the representation of defendant by plaintiff’s
former attorney, until the earlier case involving plaintiff was brought up in
a deposition, failed, as Rule 1.9 covered more than the disclosure of

confidential information. Conley v. Chaffinch, 431 F. Supp. 2d 494 (D.
Del. 2006).
In a custody modification proceeding between parents of a minor child,
a father’s request to disqualify the mother’s counsel due to counsel’s prior
representation of the father’s mother was denied, as there was no conflict
of interest under Law. R. Prof. Conduct 1.7(a) and Law R. Prof
e than the disclosure of

confidential information. Conley v. Chaffinch, 431 F. Supp. 2d 494 (D.
Del. 2006).
In a custody modification proceeding between parents of a minor child,
a father’s request to disqualify the mother’s counsel due to counsel’s prior
representation of the father’s mother was denied, as there was no conflict
of interest under Law. R. Prof. Conduct 1.7(a) and Law R. Prof. Conduct
1.9(a) where counsel had previously represented the father’s mother in
estate and divorce matters, the representation for the most part had
occurred prior to the child’s birth, counsel had not met the father during
representation of the mother, and a balancing of the competing interests
was in favor of the mother’s retention of her counsel rather than the
possible minimal prejudice that the father might suffer; the father failed to
show that he would suffer prejudice as a result of the continued
representation, and accordingly, he did not meet his burden of showing the
need for disqualification by clear and convincing evidence. G. M. v. E. T.
W., 2006 Del. Fam. Ct. LEXIS 153 (Del. Fam. Ct. Sept. 12, 2006).
During challenge to merger process, defendant merger parties moved to
disqualify the law firm retained to advise plaintiff merger challengers
because the law firm had access to confidential information regarding 1 of
the merger parties from a prior merger case; the court declined to
determine whether a conflict of interest existed, but denied the motion to
disqualify due to the delay in raising the issue, plus the harm that would
result to 1 merger challenger if forced to change law firms. Express
Scripts, Inc. v. Crawford, 2007 Del. Ch. LEXIS 18 (Del. Ch. Jan. 25, 2007)
dential information regarding 1 of
the merger parties from a prior merger case; the court declined to
determine whether a conflict of interest existed, but denied the motion to
disqualify due to the delay in raising the issue, plus the harm that would
result to 1 merger challenger if forced to change law firms. Express
Scripts, Inc. v. Crawford, 2007 Del. Ch. LEXIS 18 (Del. Ch. Jan. 25, 2007).
Counsel representing the wife in a divorce proceeding did not have to be
disqualified from that representation where a paralegal in the husband’s
firm stopped working for that firm and went to work for the law firm
representing the wife as: (1) the paralegal had performed a minimal amount
of work on the case; (2) the paralegal and wife’s counsel had maintained
a “cone of silence” on the matter by not speaking about it, minimizing
the possibility that confidential information could be passed along; and
(3) no showing had been made regarding a breach of client
confidentiality in violation of Law R. Prof. Conduct 1.9(b) or 1.10(c). In re
Marriage of C., 2008 Del. Fam. Ct. LEXIS 124 (Del. Fam. Ct. Oct. 6,
2008).

Attorney who previously represented a doctor in a medical negligence
claim against the doctor was disqualified from representing a patient and
that patient’s spouse in their medical negligence claim against the doctor,
as there was an irreconcilable conflict of interest under Law. R. Prof.
Conduct 1.9(a); the 2 actions were substantially related and the gravamen
of the claims were the same. Fernandez v. St. Francis Hosp., 2009 Del.
Super. LEXIS 287 (Del. Super. Ct. Aug. 3, 2009).
In a patent infringement suit against an electronics company, an
attorney and the attorney’s firm were disqualified under Law. R. Prof.
Conduct 1.9 from representing plaintiff where: (1) the attorney had
represented the company in an earlier suit, while working at a second firm;
e claims were the same. Fernandez v. St. Francis Hosp., 2009 Del.
Super. LEXIS 287 (Del. Super. Ct. Aug. 3, 2009).
In a patent infringement suit against an electronics company, an
attorney and the attorney’s firm were disqualified under Law. R. Prof.
Conduct 1.9 from representing plaintiff where: (1) the attorney had
represented the company in an earlier suit, while working at a second firm;
(2) the subject matter of the earlier suit concerned the same memory chip
technology at issue in instant suit; (3) the appearance of impropriety was
reflected in the fact that the attorney’s representation of the company was
not thoroughly vetted at the time the attorney began working at the firm;
(4) the firm’s conflict review was limited to what amounted to a word
search; and (5) the company was not alerted to the attorney’s representation
of plaintiff in the case at bar. Apeldyn Corp. v. Samsung Elecs. Co.., 660
F. Supp. 2d 557 (D. Del. 2009).
Even if there was a conflict between counsel’s present and former clients’
interests pursuant to Law. Prof. Conduct R. 1.9(a), where defendants
failed to show a violation so extreme that it called into question the
fairness or the efficiency of the proceeding involving the validity of a
corporate loan, disqualification of counsel under Ch. Ct. R. 170 was not
warranted. Manning v. Vellardita, 2012 Del. Ch. LEXIS 59 (Del. Ch. Mar.
28, 2012).
Nonparties were not entitled to disqualify an attorney or a law firm
from representing a seized insurer based on the attorney’s former
representation of 1 of the nonparties, a limited liability company (LLC)
that purportedly owned 99% of the insurer, because: (1) the firm would
have acquired knowledge of who controlled the LLC through
representation of the insurer; and (2) vague and unsupported allegations of
what the attorney “knew” were insufficient to justify disqualification. In re
Rehab. of Indem. Ins. Corp., 2014 Del. Ch. LEXIS 23 (Del. Ch. Feb. 19,
2014).
limited liability company (LLC)
that purportedly owned 99% of the insurer, because: (1) the firm would
have acquired knowledge of who controlled the LLC through
representation of the insurer; and (2) vague and unsupported allegations of
what the attorney “knew” were insufficient to justify disqualification. In re
Rehab. of Indem. Ins. Corp., 2014 Del. Ch. LEXIS 23 (Del. Ch. Feb. 19,
2014).

No conflict of interest existed in a slip and fall case because counsel’s
previous representation of the property owner in an unrelated case was not
shown to create a substantial risk of disclosure of material confidential
information; indirect advantage from knowing the owner’s settlement
philosophy, and a likelihood the owner had mentioned the slip and fall
incident, would be mitigated by an insurer’s assuming the defense. Harper
v. Beacon Air, Inc., 2017 Del. Super. LEXIS 99 (Del. Super. Ct. Mar. 2,
2017).
Lender was not entitled to disqualify the borrower’s counsel due to
failure to show by clear and convincing evidence the existence of any
prejudice in the fairness of the proceedings or that an alleged conflict
existed; an alleged corporate takeover of the borrower through the exercise
of the lender’s alleged rights under the pledge agreement did not form a
proper basis for counsel’s disqualification. Triumph Mortg. Corp. v.
Glasgow Citgo, Inc., — A.3d —, 2018 Del. Super. LEXIS 178 (Del. Super.
Ct. Apr. 19, 2018)
stence of any
prejudice in the fairness of the proceedings or that an alleged conflict
existed; an alleged corporate takeover of the borrower through the exercise
of the lender’s alleged rights under the pledge agreement did not form a
proper basis for counsel’s disqualification. Triumph Mortg. Corp. v.
Glasgow Citgo, Inc., — A.3d —, 2018 Del. Super. LEXIS 178 (Del. Super.
Ct. Apr. 19, 2018).
Defendant’s motion to disqualify counsel based on a conflict of interest
was granted because: (1) the law firm employed by plaintiff had
previously represented the ultimate beneficiary of the insurance policy
issued by plaintiff; (2) plaintiff’s interests were directly adverse to the
ultimate beneficiary’s interests; (3) the law firm’s inquiry into the ultimate
beneficiary’s practices in 2010 potentially uncovered conduct that informed
the truth or falsity of the allegations in the current suit, constituting the
same matter and not merely a similar matter; (4) no purported consent
from defendant relieved the law firm of its obligations under this rule;
and (5) the prejudice to defendant outweighed the inconvenience to
plaintiff. Sun Life Assur. Co. of Can. v. Wilmington Sav. Fund Soc’y, F.S.B.,
— A.3d —, 2019 Del. Super. LEXIS 663 (Del. Super. Ct. Dec. 19, 2019).
Trial court adhered to its prior determination to disqualify plaintiff’s
counsel because: (1) counsel previously represented the ultimate
beneficiary of a life insurance policy issued by plaintiff; (2) counsel’s
work product and even attorney testimony, were potentially pivotal
evidence; and (3) given that counsel argued that its former client, the
beneficiary, was illegally wagering on the lives of others, the evidence
amply demonstrated materially adverse interests between counsel’s former
previously represented the ultimate
beneficiary of a life insurance policy issued by plaintiff; (2) counsel’s
work product and even attorney testimony, were potentially pivotal
evidence; and (3) given that counsel argued that its former client, the
beneficiary, was illegally wagering on the lives of others, the evidence
amply demonstrated materially adverse interests between counsel’s former

client and plaintiff. Sun Life Assur. Co. v. Wilmington Sav. Fund Soc’y, —
A.3d —, 2020 Del. Super. LEXIS 158 (Del. Super. Ct. Apr. 9, 2020),
vacated, dismissed, — A.3d —, 2021 Del. Super. LEXIS 294 (Del. Super.
Ct. 2021).
— “Former client status”.
In order to disqualify an attorney more facts of a relationship are needed
than a simple statement of prior work done in a superficially similar area.
Satellite Fin. Planning Corp. v. First Nat’l Bank, 652 F. Supp. 1281 (D.
Del. 1987).
Attorney who represented a parent in a custody hearing violated this
Rule where the attorney had previously represented the opposing parent in
a custody matter involving the same child and no consent was obtained
from the opposing parent. In re Mekler, 689 A.2d 1171 (Del. 1996).
General information regarding a corporate client’s business practices is
not enough to deny representation by a present party’s chosen counsel;
knowledge of specific facts gained in a prior representation, relevant to the
matter in question, ordinarily will preclude representation. Sanchez-Caza
v. Estate of Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept.
16, 2004)
1 (Del. 1996).
General information regarding a corporate client’s business practices is
not enough to deny representation by a present party’s chosen counsel;
knowledge of specific facts gained in a prior representation, relevant to the
matter in question, ordinarily will preclude representation. Sanchez-Caza
v. Estate of Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept.
16, 2004).
An appropriate test for determining whether matters are substantially
related for conflict purposes involves a court considering the nature and
scope of the prior representation, the nature and scope of the present
lawsuit, and whether the client may have revealed relevant confidential
information to its counsel during the prior representation, and if so,
whether the confidential information could be used against the former
client in the current lawsuit; two matters may also be substantially related
if there 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. Sanchez-Caza v.
Estate of Whetstone, 2004 Del. Super. LEXIS 300 (Del. Super. Ct. Sept. 16,
2004).
— Shareholders’ derivative suits.
Counsel representing a shareholder class in a derivative suit was not
subject to being disqualified for advocating the adoption of a settlement

proposal to which some members of the class objected. In re M&F
Worldwide Corp. S’holders Litig., 799 A.2d 1164 (Del. Ch. 2002).
Plaintiffs, two directors of a family corporation and the corporation,
failed to prove third director’s use of long-time corporation and family
attorneys to defend against that director’s removal by shareholders in a
declaratory judgment action threatened to undermine fairness and integrity
of proceeding or violate Del. Law. R. Prof. Conduct 1.7, 1.9, 1.13(e), and
1.16(b)(1). Unanue v. Unanue, 2004 Del. Ch. LEXIS 37 (Del. Ch. Mar. 25,
2004)
and the corporation,
failed to prove third director’s use of long-time corporation and family
attorneys to defend against that director’s removal by shareholders in a
declaratory judgment action threatened to undermine fairness and integrity
of proceeding or violate Del. Law. R. Prof. Conduct 1.7, 1.9, 1.13(e), and
1.16(b)(1). Unanue v. Unanue, 2004 Del. Ch. LEXIS 37 (Del. Ch. Mar. 25,
2004).
In a derivative action, defendants’ assertions failed to demonstrate that
representation by the former chief legal counsel of a parent company was
substantially related to the instant lawsuit involving a sale of the parent’s
and non-wholly owned subsidiary’s assets, because the counsel was not
challenging a series of transactions in which counsel was a key participant,
but rather was challenging the allocation in a single transaction from
whose negotiations counsel was actively excluded; additionally, counsel
had a role as a member of the subsidiary in approving the transactions,
distinct from the role as counsel of the parent. Bakerman v. Sidney Frank
Importing Co., 2006 Del. Ch. LEXIS 180 (Del. Ch. Oct. 10, 2006).
Professional conduct.
— Candor to the tribunal.
Even though there was no cause to disqualify counsel or revoke
counsel’s admission pro hac vice status, where counsel failed to disclose a
colorable claim of conflict between former and present clients pursuant to
Law. Prof. Conduct R. 1.9(a), such evidenced a lack of candor to the court
and warranted referral to the disciplinary authorities. Manning v. Vellardita,
2012 Del. Ch. LEXIS 59 (Del. Ch. Mar. 28, 2012).

Del. Rules of Prof'l Conduct Rule 1.10

## Nearby sections

- [Del. Lawyers' R. Prof'l Conduct 1.0 Rule 1.0. Terminology](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_0.md)
- [Del. Lawyers' R. Prof'l Conduct 1.1 Rule 1.1. Competence](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_1.md)
- [Del. Lawyers' R. Prof'l Conduct 1.2 Rule 1.2. Scope of representation](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_2.md)
- [Del. Lawyers' R. Prof'l Conduct 1.3 Rule 1.3. Diligence](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_3.md)
- [Del. Lawyers' R. Prof'l Conduct 1.4 Rule 1.4. Communication](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_4.md)
- [Del. Lawyers' R. Prof'l Conduct 1.5 Rule 1.5. Fees](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_5.md)
- [Del. Lawyers' R. Prof'l Conduct 1.6 Rule 1.6. Confidentiality of information](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_6.md)
- [Del. Lawyers' R. Prof'l Conduct 1.7 Rule 1.7. In addition, such a lawyer may be subject to statutes and government regulations regarding conflict of interest. Such statutes and regulations may circumscribe the extent to which the government agency](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_7.md)
- [Del. Lawyers' R. Prof'l Conduct 1.8 Rule 1.8. For former client conflicts of interest, see Rule 1.9. For conflicts of interest involving prospective clients, see Rule 1.18. For definitions of](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_8.md)
- [Del. Lawyers' R. Prof'l Conduct 1.9 Rule 1.9. Duties to former clients](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_9.md)
- [Del. Lawyers' R. Prof'l Conduct 1.10 Rule 1.10. Imputation of conflicts of interest: General rule](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_10.md)
- [Del. Lawyers' R. Prof'l Conduct 1.11 Rule 1.11. Special conflicts of interest for former and current government officers and employees.](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_11.md)
- [Del. Lawyers' R. Prof'l Conduct 1.12 Rule 1.12. Former judge, arbitrator, mediator or other third-party neutral.](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_12.md)
- [Del. Lawyers' R. Prof'l Conduct 1.13 Rule 1.13. Organization as client](https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_13.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/SRULES_DE_DELRPC_R1_9. Check the current official text before relying on it. Not legal advice.