MaryJeanette Dee is the Co-Managing Partner of Sheppard Mullin. She serves on the Executive Committee and is based in the firm’s New York office.

In her role as a key member of the management team, MaryJeanette dedicates her efforts to fostering the growth and successful operation of the firm's practice groups, offices, and industry teams. She is actively involved in the firm’s Diversity & Inclusion Committee, Compensation Committee and Technology Committee.

Areas of Practice

Before moving into management roles at the firm, MaryJeanette’s practice was dedicated to internal investigations and regulatory and white collar criminal defense. MaryJeanette frequently represented banks, broker-dealers, investment advisers, corporate officers, financial advisors and other securities professionals in connection with domestic and cross-border investigations and inquiries by U.S. Attorney’s Offices for the Southern and Eastern Districts of New York, the SEC, the CFTC, FINRA, the NY Attorney General’s Office, the FRB, the NY Department of Financial Services and other governmental entities and self-regulatory organizations. She has conducted numerous internal investigations into a wide variety of allegations, including insider trading, trading and position valuation issues, misuse of confidential information, embezzlement, money laundering and BSA/AML issues, sanctions compliance and retail brokerage sales practice violations. Representative engagements include:

Institutional representations:

  • Representation of a global investment bank and a U.S. broker-dealer in connection with SEC and FINRA investigations involving the SEC’s Market Access Rule (Rule 15c3-5);
  • Representation of a Korean bank in connection with potential US sanctions violations;
  • Representation of the Private Bank division of a global investment bank in connection with FINRA, SEC and state securities regulatory inquiries and investigations;
  • Representation of the Audit Committee of a non-profit organization in connection with whistleblower allegations of contracting irregularities;
  • Representation of global investment banks and investment advisers in connection with insider trading investigations;
  • Representation of a broker-dealer in connection with a FINRA “marking the close” investigation;
  • Representation of global investment bank in connection with whistleblower allegations of improper marking-to-market of equity derivatives;
  • Representation of a global financial institution in connection with FINRA investigation of its retail securities lending program.

Individual representations:

  • Representation of global bank personnel in connection with SEC FCPA investigation regarding Asia hiring practices;
  • Representation of a financial advisor in connection with money laundering investigation by the U.S. Attorney’s Office for the Southern District of Florida;
  • Representation of traders in connection with ISDAfix investigations by the CFTC;
  • Representation of a financial advisor in connection with a FINRA investigation relating to managed futures products;
  • Representation of a senior AML Risk Officer in FINRA AML practices investigation;
  • Representation of ETF professional in connection with an SEC investigation regarding potential conflicts of interest;
  • Representation of senior mortgage finance professionals in RMBS-related investigations and litigations;
  • Representation of financial advisors in connection with FINRA investigation into CRD disclosures;
  • Representation of a compliance professional in SEC information barriers investigation;
  • Representation of a trader in FINRA investigation relating to alleged kickback scheme;
  • Representation of operations professionals in connection with SEC “soft dollar” investigation;
  • Representation of a retail branch manager in connection with FINRA Ponzi scheme investigation.

In 1993, MaryJeanette served as Special District Attorney in the Middlesex County District Attorney’s Office in Massachusetts. She obtained convictions in bench and jury trials for credit card fraud, aggravated assault, stalking and other felony crimes.

MaryJeanette’s work and professionalism have earned her recognition as a top white collar criminal defense lawyer. She has been awarded an AV® Rating by Martindale-Hubbell® Peer Review. In multiple years the Legal 500 directory has recognized her accomplishments in this area. She has also been named a New York Super Lawyer in white-collar criminal defense and by Best Lawyers in America for White Collar. She has also served as a Trustee of the Harvard Law School Alumni Association of New Jersey and is a member of a number of professional associations.



Best Lawyers in America, Best Lawyers, 2015-2024

Legal 500, 2007, 2008, 2011, 2013, 2016

New York Super Lawyers, 2008-2014, 2016-2022

AV® Rated, Martindale-Hubbell®


Speaking Engagements

  • Speaker, "Defending the Gatekeeper: When In-House Counsel and Compliance Professionals are Investigated," Storming the Gatekeepers: When Compliance Officers and In-House Lawyers Are at Risk 2019, September 4, 2019
  • Speaker, "The Government’s Perspective: Duties of In-House Counsel and Compliance Professionals," Storming the Gatekeepers: When Compliance Officers and In-House Lawyers Are at Risk 2018, September 5, 2018
  • Speaker, "Regulatory Panel," STANY Annual Conference & Reception, April 19, 2018
  • Speaker, "Is Everything Privileged? Limitations on Privilege in the Area of Compliance," PLI's Storming the Gatekeepers: When Compliance Officers and In-House Lawyers Are at Risk 2017, September 27, 2017
  • Speaker, "Commencing the Investigation: Considerations at the Outset," PLI's Internal Investigations 2017, June 19, 2017
  • Speaker, "Selecting and Managing Outside Counsel & Resources," 2017 SIFMA Compliance & Legal Society Annual Seminar, March 19 - 22, 2017
  • Speaker, “Handling A Regulatory Investigation,” 2016 SIFMA Compliance & Legal Society Annual Seminar, March 13 - 16, 2016
  • Speaker, "Conducting the Investigation," PLI's Internal Investigations 2015, June 2015
  • Speaker, "Handling a Regulatory Investigation," SIFMA Compliance and Legal Annual Seminar, March 2015
  • Speaker, "Concluding the Investigation," PLI's Internal Investigations 2014
  • Speaker, "Internal Investigations," SIFMA Compliance & Legal Society Annual Seminar, 2011-2013
  • Panelist, "Bet the Company Litigation 2010: Best Practices for Complex Cases," PLI Conference
  • Panelist, "Bet the Company Litigation 2009: Best Practices for Complex Cases," PLI Conference
  • Presenter, "Internal Investigations: Balancing Competing Concerns & Objectives"
  • Moderator, "Managing Litigation On Multiple Fronts: Parallel Criminal, SEC, and Plaintiff Proceedings"
  • Moderator, 6th Securities Litigation Conference
  • Panelist, "Overlapping Civil Litigation and Government (Regulatory/Department of Justice) Investigations," PLI Seminar
  • Moderator, "Parallel Criminal, SEC and Plaintiff Proceedings"
  • Speaker, "Interlinking the U.S. and Canada through Overcoming and Managing Multi-Jurisdictional Obstacles"
  • Presenter, "Overlapping Civil Litigation and Government (Regulatory/Department of Justice) Investigations," PLI Seminar




J.D., Harvard Law School, 1990, cum laude

B.A., Wells College, summa cum laude


  • New York
  • U.S. District Courts for the Southern and Eastern Districts of New York
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