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Mark D. Sweet
+1 202 408 4162

901 New York Avenue, NW
Washington, DC 20001-4413

+1 202 408 4000
Fax +1 202 408 4400

Bar and Court Admissions

  • District of Columbia
  • U.S. Patent and Trademark Office


  • Catholic University of America, Columbus School of Law
    J.D., 1998
  • College of William and Mary
    B.S., Chemistry, 1988

Mark D. Sweet


Mark Sweet, managing partner of Finnegan, focuses his practice on portfolio analysis; due diligence investigations; interference proceedings; reissue and reexamination proceedings; preparing patentability, validity, and infringement opinions; and client counseling. Mr. Sweet's technical expertise is diverse and includes working with technologies involving pharmaceuticals, agricultural chemicals, polymers, industrial coatings and films, and clean energy and renewable resources such as photovoltaics, fuel cells, renewable feedstocks, hydrogen-based fuel, and bioplastics.

Mr. Sweet is a registered patent attorney with extensive experience handling procurement matters before the U.S. Patent and Trademark Office (USPTO), including patent application drafting and prosecution, conducting examiner interviews, filing appeals to and presenting oral arguments before the Patent Trial and Appeal Board (PTAB) of the USPTO, interference proceedings, reissue proceedings, and reexamination proceedings. Mr. Sweet also has significant experience in inter partes review (IPR) and post grant review (PGR) proceedings.

Mr. Sweet is a frequent lecturer at legal and corporate seminars on a variety of intellectual property topics, including patent procurement and procedures, such as the provisions of the America Invents Act (AIA). Recent topics include effective use of AIA post-grant proceedings; global patent prosecution and enforcement; strategic patent portfolio management and monetization, and changes to U.S. patent laws.


  • Represents a leading specialty chemical manufacturer in matters including several IPR and PGR proceedings, due diligence, patent portfolio development, and counseling.
  • Represents one of the world's leading manufacturers of construction equipment and diesel engines in prosecution and counseling matters that include several IPRs.
  • Manages the entirety of intellectual property work for several clean energy companies including managing each company's worldwide patent portfolio, which are directed to photovoltaic devices, fuel cells, and hydrogen-based fuels.
  • Served as leader of the firm's chemical and metallurgical practice group, 2015-2016; a member of the firm's management committee, 2012-2015; and as the firm's hiring partner in the Washington, D.C. office, 2008-2012.
  • Served as primary examiner at the USPTO, where he handled polymer-based technologies, 1995-1998; and patent examiner, 1988-1994.

Professional Recognition

  • Recognized by The Legal 500 U.S. for patent prosecution, re-examinations, and post-grant proceedings, 2013-2017; and as a leading lawyer, 2015-2017.
  • Recognized as a leading patent prosecutor in the D.C. area by Intellectual Asset Management, 2013-2017.

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