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David H. Marion Senior Counsel

Philadelphia, PA | Direct 215.864.6870Fax 215.789.6675
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David Marion concentrates his practice on complex business litigation, antitrust and securities class actions, legal malpractice defense, communications law and alternate dispute resolution. David acts as both plaintiffs and defense counsel in such litigation. 

David has achieved numerous noteworthy victories including seven-figure jury verdicts in an unfair competition case against a major broadcast network, and in a vertical price-fixing case; defense of a major public utility in a precedent-setting federal ERISA class action; and victories in the U.S. Supreme Court and numerous state and federal appellate courts. He was appointed by the U.S. District Court as Receiver in a Securities and Exchange Commission civil action involving a Ponzi scheme, and as special master in complex federal multi-district litigation. 

Representative Matters

  • Successfully argued in the United States Supreme Court in a case establishing plaintiffs' burden to prove falsity in First Amendment libel cases
  • Successful appeals before the Pennsylvania Supreme Court, including a case liberalizing grant of summary judgment for defendants
  • Successfully represented a client before the Third Circuit United States Court of Appeals in a precedent-setting ERISA case
  • Secured the affirmance of a seven-figure unfair competition verdict before the Third Circuit United States Court of Appeals
  • Secured a seven-figure jury verdict before the United States District Court of the Eastern District of Pennsylvania against a munitions manufacturing company
  • Successfully achieved affirmance by the Second Circuit United States Court of Appeals of the grant of summary judgment against a group of craft labor unions 
  • Currently serving as Special Master appointed by EDPA Judge Cynthia Rufe in the Generic Pharmaceuticals Price-Fixing Antitrust Cases

Recognition & Involvement

David was elected Chancellor of the Philadelphia Bar Association, is a former President of the Philadelphia Lawyers Club and is the National Chancellor of the Tau Epsilon Rho Law Society. He was elected as a Fellow of the American College of Trial Lawyers, the International Academy of Trial Lawyers and the American Academy of Appellate Lawyers, and holds leadership positions in several non-profit organizations.  

David received the James Wilson Award, the highest honor Penn Law School extends to a distinguished alumnus, and was the recipient of the Judge Learned Hand Award from the American Jewish Committee. He has been listed in Chambers USA as a leading lawyer in commercial litigation since the honor's inception in 2003 and is described as a "very highly regarded trial attorney." Since 2004, in surveys of his peers, David has been selected as a Pennsylvania "Super Lawyer." He is uniquely listed by Best Lawyers in America in six categories of law practice: Appellate Practice, Bet-the-Company Litigation, Commercial Litigation, First Amendment Law, Legal Malpractice Law, and Media Law. David was recently recognized by Best Lawyers as the 2019 Legal Malpractice Law "Lawyer of the Year" award winner in Philadelphia. He was also named one of The Philadelphia Inquirer's "Influencers of Law" for Litigation and Dispute Resolution.



Bar and Court Admissions



University of Pennsylvania Law School, JD, magna cum laude, Editor in Chief, Penn Law Review

University of Pennsylvania, Wharton School, BS in Econ


Anti-Defamation League Board of Directors

Tau Epsilon Rho Law Society, National Chancellor

Philadelphia Bar Association, Former Chancellor

Lawyers Club of Philadelphia, Former President

Rotary Club of Philadelphia, Former President

Federation of Jewish Agencies, Board of Directors

Philadelphia Bar Association - Former Chancellor, Chair of Federal Courts Committee, Bench-Bar Conference Committee, Senior Lawyers Committee

University of Pennsylvania Law Alumni Society, Former President

University of Pennsylvania Law School, Board of Overseers, Former Member

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