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Finnegan
Mark D. Sweet
Partner
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vCard
  • 901 New York Avenue, NW
  • Washington, DC 20001-4413
+1 202 408 4162
mark.sweet@finnegan.com mark.sweet@finnegan.com

Mark D. Sweet

Partner

  • +1 202 408 4162 +1 202 408 4162
  • mark.sweet@finnegan.com mark.sweet@finnegan.com
  • 901 New York Avenue, NW
  • Washington, DC 20001-4413
  • vCard
Mark Sweet focuses his practice on portfolio analysis; due diligence investigations; interference proceedings; reissue and reexamination proceedings; preparing patentability, validity, and infringement opinions; and client counseling.

Mark 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. Mark also has significant experience in inter partes review (IPR) and post grant review (PGR) proceedings.

Mark represents a leading specialty chemical manufacturer in matters, including several IPR and PGR proceedings, due diligence, patent portfolio development, and counseling. He also represents one of the world's leading manufacturers of construction equipment and diesel engines in prosecution and counseling matters that include several IPRs. He 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.

Mark'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. He served as a primary examiner at the USPTO, where he handled polymer-based technologies.

Mark 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.

The Legal 500 U.S. has recognized Mark for his work in patent prosecution, reexaminations, and post-grant proceedings. He was named a Global Leader and as a leading patent prosecutor in the D.C. area by Intellectual Asset Management. In Acritas Stars, clients have touted his "advice in strategic planning and analysis of complex situations" as well as "his responsiveness... [and] ability to focus in on the issues that the business is interested in."

Mark has held several firm leadership roles over the years. He served as managing partner, as firm chair, as leader of the chemical and metallurgical practice group, and as the firm's hiring partner in the Washington, D.C. office. He also served a three-year term on the management committee.

Insights

Lecture

2025 IP (Intellectual Property) Due Diligence & Freedom to Operate in Practice Training Course 2025 IP (Intellectual Property) Due Diligence & Freedom to Operate in Practice Training Course

March 6-7, 2025

Webinar

Webinar

USPTO Examiner Interview Strategies: Preparing for and Conducting Interviews to Advance Patent Prosecution USPTO Examiner Interview Strategies: Preparing for and Conducting Interviews to Advance Patent Prosecution

June 27, 2024

Webinar

Conference

2023 IP & Ski Conference 2023 IP & Ski Conference

January 4-7, 2023

Vail

Webinar

Developing New Revenue Streams During COVID Through Intellectual Property Developing New Revenue Streams During COVID Through Intellectual Property

April 21, 2021

Webinar

Webinar

Introduction to a Legal Career and Intellectual Property Law

Introduction to a Legal Career and Intellectual Property Law Introduction to a Legal Career and Intellectual Property Law

September 15, 2020

Webinar

Seminar

Dar Al Uloom University IP Workshop Dar Al Uloom University IP Workshop

February 10, 2020

Riyadh

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Professional Recognition

"Sweet is an expert when it comes to portfolio analysis, due diligence and opinion work."

Intellectual Asset Management Patent 1000

“Sweet is in hot demand for high-level strategic oversight. He also makes a vital contribution to the side’s booming post-grant practice.

Intellectual Asset Management Patent 1000

“Among the best strategic counsellors is managing partner Mark Sweet…”

Intellectual Asset Management Patent 1000

“…a cleantech authority, Sweet manages [a] worldwide organic photovoltaic device patent portfolio, making excellent use of his carefully cultivated global network to get the best for the company.”

Intellectual Asset Management Patent 1000

"Sweet is an expert when it comes to portfolio analysis, due diligence and opinion work."

Intellectual Asset Management Patent 1000

“Sweet is in hot demand for high-level strategic oversight. He also makes a vital contribution to the side’s booming post-grant practice.

Intellectual Asset Management Patent 1000

“Among the best strategic counsellors is managing partner Mark Sweet…”

Intellectual Asset Management Patent 1000

“…a cleantech authority, Sweet manages [a] worldwide organic photovoltaic device patent portfolio, making excellent use of his carefully cultivated global network to get the best for the company.”

Intellectual Asset Management Patent 1000

News

Award/Ranking

Finnegan Earns Top Rankings in 2026 IAM Patent 1000 Guide; Nearly 60 Attorneys Ranked Finnegan Earns Top Rankings in 2026 IAM Patent 1000 Guide; Nearly 60 Attorneys Ranked

May 28, 2026

Intellectual Asset Management (IAM)

Award/Ranking

IAM Recognizes Six Finnegan Partners in its 2026 Global Leaders Guide IAM Recognizes Six Finnegan Partners in its 2026 Global Leaders Guide

October 22, 2025

Intellectual Asset Management (IAM)

Award/Ranking

50 Finnegan Attorneys Ranked in the 2025 IAM Patent 1000

50 Finnegan Attorneys Ranked in the 2025 IAM Patent 1000

June 2, 2025

Intellectual Asset Management (IAM)

Award/Ranking

Nine Finnegan Partners Recognized in the Inaugural Lawdragon 500 Leading Global IP Lawyers

Nine Finnegan Partners Recognized in the Inaugural Lawdragon 500 Leading Global IP Lawyers

May 23, 2025

The Lawdragon 500: Leading Litigators in America

Award/Ranking

Seven Finnegan Attorneys Recognized in the 2025 IAM Global Leaders Guide

Seven Finnegan Attorneys Recognized in the 2025 IAM Global Leaders Guide

October 23, 2024

Intellectual Asset Management (IAM)

Award/Ranking

46 Finnegan Attorneys Ranked in 2024 IAM Patent 1000

46 Finnegan Attorneys Ranked in 2024 IAM Patent 1000

June 6, 2024

Intellectual Asset Management (IAM)
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Admissions and Education

Admissions

  • U.S. Patent and Trademark Office
  • District of Columbia
  • U.S. Court of Appeals, Federal Circuit

Education

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

Mark's Practices

Patent Office Invalidation Proceedings
Derivations
Ex Parte Reexamination (EPR)
Interferences
PTAB Invalidation Proceedings: IPR and PGR
Prosecution and Portfolio Management
Due Diligence
Ex Parte Reexamination (EPR)
IP Portfolio Management
Opinions and Counseling
Patent Drafting and Prosecution
Patent Reissues

Mark's Industries

Chemicals, Industrials, and Materials
Chemical
Manufacturing
Textiles
Energy
Clean Energy and Renewables
Oil and Gas
Life Sciences
Biotechnology
Pharmaceutical

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